Ideas and suggestions.

*Maybe it has long been time to change the spell schools in Heroes 3, huh? What do I mean, maybe? Definitely!*

*Everyone levels Earth/Air - how is a mage supposed to win through Water and Fire? Water is essentially a purely warrior school: teleport a strong stack into the thick of things, but for a mage there is nothing useful there against a warrior with winning stats; Prayer is often still too little.*

*Air has five level-5 spells - Another reason everyone levels Earth/Air is that there is a high chance that in a level-5 Mage Guild there will be something from Earth or Air, while Water has only one level-5 spell, and even that is Summon Elemental*

*Countering elements - When people play through Implosion or Chain Lightning, why must you necessarily level the very same element to counter it? This is the second reason the magic schools lack variety: the initiator takes the element that is effective for him, while the defender is forced to level the same element to counter it. Water sucks, Fire does not, but there is no need to improve it.*
*Would it not be better, in order to counter one element or another, to level a different one, so there would be variety?*
*Looking at the spells, I saw that most Fire spells are countered by Earth, Air by Fire, Water by Air, and Earth by Water. Whatever Earth puts on, Water removes everything, which others cannot do (Implosion is the exception); and Earth has Anti-Magic against Fire Armageddon, so in the end everyone suffers, both enemy and ally, but one completely healthy stack remains thanks to Anti-Magic. Earth also has many spells against Fire that reduce damage, and so on, which often makes you not care about Bloodlust*
*Conclusions:*
So why not put Protection from Fire not in the Fire school but in Earth, protection from Air in Fire, protection from Water in Air, and protection from Earth in Water.*
*Earth smothers fire, water wears away stone*
*Air has Fly and Dimension Door; why does it need so much? And why does Water teleport units, while teleporting the hero is suddenly Air? Many people say to make both teleports Water, but there is a nuance: would Water Walk not die in that case if it has a better alternative, unless Water Walk is buffed? But one thing I know for sure: two strong map-control spells in Air is definitely too much.*

*Then spell variety will appear: one player takes Solmyr, you take Fire Magic to counter him, he foresees this and takes Earth Magic (Chain Lightning + Implosion), then he also takes Water, and now all 4 schools are in the battle*

*Should it be done exactly the other way around? For example, Water counters not Earth but Air, and in the same counterclockwise sequence? What can I say about that... I have not calculated which sequence to use, I do not know! But putting protection from a given element in other elements is definitely the key to solving variety!*
PS: I wrote this article about 2 hours ago, and now I am adding this little one-line message; I could not resist))) > Only now did it dawn on me that this reminded me of the Avatar cartoon: Air mastered Water easily, struggled with the opposite, Earth, and Fire was considered extremely dangerous for him.

*[But the Earth school is opposite to Air, so why not make Air counter Earth?]* Because then there again will be no variety: it will be Earth/Air all over again. In addition, I have an argument for that case: Earth has Animate Dead for undead and Resurrection for the living; for the dead there is Death Ripple, and for killing undead, SURPRISE, now it is the Air element. Strange? A little... but that does not make those elements counters to one another; they are equal! Destroy Undead and Death Ripple perform the same function equally, so why should they counter each other? They are opposite elements: Slow and Haste, Bless and Curse; they fight each other on equal terms. The element that counters another should not be from the opposite elements.*
Fire is fanned by Wind and Lightning; Earth smothers Fire; Water wears away Stone...

Difficulties: *Or perhaps leave Water Magic movement by sea and teleport in battle, and make the map teleport a Fire spell, as a kind of opening of portals. In that case everyone would have their own map control, and Water Walk would not lose relevance because a portal would not replace it. I am worried that if the map portal is moved to Water, Water Walk will become unnecessary. This is hard, it needs thought... but for some reason my teeth itch to deprive Fire of map control while making it destructive. Still, the question remains acute: why will Water Walk be needed if Dimension Door exists, unless it is not a level-4 spell but level 5, and Water Walk is buffed?*

PS: Now I will also talk not about balance for everyone, but a little from myself, in dreams) It was always a little sad that Protection from Water exists but is essentially unnecessary; Water Magic has no decent damage-dealing spells in principle, only useless ones... I also always dreamed that Ice Bolt would reduce a unit's speed by one, worse than Slow but still, you deal damage and slightly slow at the same time) And I never understood why two dispel-type spells are needed, namely Cure and Dispel. It is too easy to pull dispel when there are two variations. I do not deny that Cure does not remove everything and only works on allies, but somehow it still has painfully many functions in what it removes. Often Cure is enough to remove everything harmful from yourself, and when playing through Water Magic you essentially do not need Dispel against curses.

*It also really annoys me on small maps when someone takes Solmyr and you are forced to level the same element as he does in order to level Protection from Air, if you are lucky enough to pull that very Protection from Air and also level it to 3 in order to counter him, while he, knowing his advantage, will try to reach you faster before you get lucky and learn it.*
*Sometimes it seems to me, especially on small maps, that protection from elements should not only be in different schools but should also give bonuses earlier. At first I thought of making mass elemental protection level 1, but that would also ruin balance... I do not yet see a solution to this situation; it is difficult... but maybe elemental protection should become mass already at level two? And at level three its effectiveness should be raised.*

I also described what could be done with the Water school - Read below; I answered the idea to some participants.
If the idea of a double turn for the Water Magic school is approved, then Water will not need a strong new damage spell. Frost Ring is cheap in mana, and if it is used twice per turn, the damage there should be decent.

Perhaps not every spell should grant the right to a repeated Water Magic action, but only some of them, those that cost, say, less than 10 mana (that is, 9 or lower). This would give Arch Magi, or conversely Pegasi, a way to counter part of the Water Magic school by making its spells more expensive, so the opponent would not have access to the variety of Water Magic. For example, make Forgetfulness at least 12-10 mana rather than 9, so after using it you could not use another spell; and conversely, after a cheap spell you could no longer choose an expensive one.

FINALLY:

I also want to talk about the specialties of some heroes, such as

Stone Skin: Stone Skin adds another +3 Defense for level 1-2 creatures, +2 Defense for levels 3-4, +1 Defense for levels 5-6, and +0 for level 7.

It always surprised me: why does the spell give everyone +6 Defense, while with the specialty the higher the level, the less it gives? Would they really become imbalanced from that? I understand, of course, that level-1 creatures need stats more than level-7 creatures, but it still looks strange somehow... or maybe the creators approached it lazily?

But what outrages me most is this, a blunt copy, despite going in the opposite direction

Hero specialty - Weakness: Weakness additionally reduces by -3 for levels 1-2, -2 for levels 3-4, -1 for levels 5-6, and -0 for level 7

How does that make any sense?! For level-1 creatures, even -1 Attack is already significant for low-level creatures, and here it is a whole -3! Whereas for level 5-7 creatures, -1 Attack is not significant, and even -3 hardly makes a terribly strong difference for creatures of that level. How did the creators do their calculations?

I think Eagle Eye's percentage chance should be kept, not turned into an imba skill and not overstuffed with lots of bonuses. Leave it as it is, but I fully agree that spells should be learned not after battle but during it; after battle there can already be a chance to learn spells unrelated to the battlefield.

The artifact idea is interesting too.

There are simply heroes such as "Tiva" from Fortress, whose specialty is Eagle Eye, increasing the chance to learn spells per level. Because of that I think the percentage should be kept, and perhaps such heroes should be given the ability to copy fifth-level spells.

I already described above how to make it less of a strong imba and add variety, and explained what others have and what they do not, especially concerning where and how many level-5 school spells there are. My option balances better, because protection from an element should not be in that same element; otherwise everyone will play one element for attack and counter at the same time.

No!

Or then it would be simpler just to give Dimension Door to the Water Magic school.

Well, if the perfectionists now object here, saying that Fire would supposedly be useless then, since all schools would have map control except Fire, I can suggest this idea too, though I am still very doubtful whether it is right; still, I will voice it: Water gets Water Walk (increased distance so it can compete with Air, or even boarding a ship without penalty at level 5, I have no idea), Air gets Fly, Earth gets Town Portal, and Fire, as demon portals, gets all teleports.

Then each school would have its own style of map control.

But Water worries me a lot in that case. If its in-battle teleport is taken away, then what exactly will it be needed for in battle? It is still hard for me to make the right decision here...

Although it always seemed to me that Fire could be given something uber-annoying, so that you pay for having no map control by carrying a strong assortment of spells, sacrificing mobility.

I enjoyed reading you; reread my first post at the very top.

I also read about [the "Storm" spell, which is weaker than Armageddon but still], and I have mixed feelings. Why is Storm needed if Armageddon exists? Spells should instead be made different from each other, not similar. This is worth working on so there is a difference between Ice Bolt and Inferno versus Frost Ring and Meteor Shower, because essentially they are the same, but Meteor wins on damage... They should bring different advantages, not do the same thing with another simply better in damage.

I also explained above that protection from elements should not be in the element itself, AND THE MOST IMPORTANT THING IN MY OPINION IS:

*Water school*
Water definitely needs some damage spell, whether a reworked Frost Ring, or perhaps Frost Ring could get some effect unlike its analogues and its damage not be raised much while adding some other damaging option, but still it should not exceed competitors.

Why? Because I see this picture: if Water is given Protection from Earth, as I suggested earlier above, then Implosion will no longer be such a dangerous spell, and Dispel also belongs to the Water school, removing all kinds of Shields and Slow; Prayer is not countered by Slow unlike Haste. In the end Water beats Earth, but Water is not that strong in damage, and I think leaving that as it is would be right, because this will no longer be its flaw but its trump card:

Water will counter Earth 
Water will still be weaker than other schools in power, but because of that, Water will have all the cheap spells in terms of mana.. (Maybe even add a spell that restores mana to the hero), and that is how Water will win!
= It will remain a weak school, but a profitable one, and it will counter the strongest school!

Advantages of Water
You level Fire, Earth, Wind: mana goes away, damage and control are substantial!
You level Water: damage is decent but not lethal; however, it is convenient for travel, counters shooters, lowers speed by one with Ice Bolt, costs little, and there is enough mana for the next battle and travel.
And in late game Earth is not a threat, and Frost Ring (or a new Water spell) will deal stable, good damage for its cost, perhaps with effects.
Blind, Slow? Again, Dispel is more profitable in mana; the enemy spends more mana on control. (Perhaps in the future the developers should think about the base cost of all spells; after all, mass spells should cost a little more mana than single-target ones.
Read below; further down I also suggested to one user that the Water Magic school could cast twice, another reason for its economy and advantage.

Conclusions:
So, Frost Ring deals average damage, but with Protection from Earth it will still hit more impressively than Implosion itself, and not to a single target, while being more efficient in mana!
Or if the idea of double use for the Water Magic school is approved, then do not change or increase Frost Ring's damage and do not add a new combat Water spell, because the damage from Frost Ring will already be decent if it can be used twice per turn.

If the idea of a double turn for the Water Magic school is approved, then in that case Water will not need a strong new damage-dealing spell. Frost Ring is cheap in mana, and if it is used twice per turn, the damage there should be enough.

Perhaps not every spell should grant the right to a repeated Water Magic action, but only some of them, those that cost, say, less than 10 mana (that is, 9 and below). This would give Arch Magi, or conversely Pegasi, the possibility to counter part of the Water Magic school by making its spells more expensive, so the opponent would not have the option of Water Magic variety. For example, make Forgetfulness at least 12-10 mana rather than 9, so after using it another spell could not be used; and conversely, after a cheap spell you could no longer choose an expensive one.

I see no point; the boots have already been nerfed, as has Logistics.

And getting such a bag of gold at the start can help a lot with winning; maybe its value should be lowered, but if so, only by one step, especially on king 200% difficulty. Getting such a bag is key to victory through fast development.

This is already some King's Bounty))) Though I have repeatedly thought that sometimes it would be cool to see the ability to cast twice in one turn, but imagine Eagle Eye combined with the Earth book and double spells? That would be imba!
If something like this is introduced... for some reason it seems more correct to attach it not exactly to a specialty, but closer to the Water book, as a weak but economical school. 
PS: By the way, thanks for the idea; I will now redo the upper posts and suggest this idea for Water Magic.

Imagine Water school level 3: using Water? Then take a repeated magic turn, but the repeat can use only Water Magic and only cheap spells. There is your solution for how weak Frost Ring deals decent damage: because it is used twice.

Oh, nice to see someone knowledgeable)

Well, imba or not imba, in Armored Princess it was nerfed hard. I suggested above how a repeated turn could be introduced: give the weak Water school the possibility of only a double turn for cheap spells, nothing more - reread it.

DD to Fire? Same as portals....

I understand, of course, that Fire is demons, they have summons and portals there, perhaps this can somehow be added for atmosphere and balanced among all schools, but each school should have its own map control for balance. If DD is taken from Earth, Earth will simply become the new useless school like Water Magic is now.

If teleport is moved to Fire, then which of the three... and what should be left to Earth? As far as I know, Air has two map-control spells at once; that is not right.

Or another scenario: simply make Fire a more destructive spell school in exchange for losing mobility.

Eagle Eye always bothered me because it could not copy map-control spells and could not learn fifth-level spells. No, that would be too much... but there are heroes specifically specialized in this skill, so why not let artifacts and the skill allow learning spells not used on the battlefield from the opponent you fought, and also fifth-level magic-school spells if your hero is built for it?

Again, the hero Tiva from Fortress: their town has at most level-3 Mage Guild, and Eagle Eye could help balance mages by letting them learn somewhat higher school spells through this skill than what they have in town, like witches of a sort (although that is what they are). But this requires a battle, and true witchers with this specialty could villainously learn others' spells up to level 5.

It is simpler to make this part of the Water book's style.

As the most useless school, that is how it will become useful. Adding this function to the other elemental schools would be too imba. 

What was normal for Heroes 8 does not mean it will be normal for Heroes 3.

Town Portal will remain Earth Magic! Otherwise the school will die.

But reread above what other changes I tossed in. After all, I have been involved in game development and balance for many decades; at present Air has 2 map-control spells (which is a lot, it does not need that many!), Earth has 1 control spell, Fire has 0, and Water has mediocre Water Walk...

2) Maybe, maybe not; in any case, for now this does not solve the problem that in order to counter one element, you yourself must study the same element as the opponent, hence the lack of variety among schools.

.

Addressing the rebalance developers

I am very glad about what you are doing. I myself have worked on balance all my life. Perhaps you already have your own ideas, and you are unlikely to consider anyone else's ideas, or my ideas and wishes, when you are already firmly focused on your own. But like any artist, and balance is a delicate matter akin to creativity, you should understand that a chance for consideration must be given. Like any artist, even when making an almost finished drawing, one must change one's mind many times, crumple the drawing without pity, and draw it again and again, many times from scratch, until a work of art emerges.

If you do listen to the ideas of people here, then know that there is one nuance! If you do everything, including my ideas, with reworking elemental protections into other magic schools and giving Water Magic repeated turns, then I predict the following: three magic schools will become popular, and Air Magic may become weaker and require an upgrade, but we shall see.  

I hope you have heard me, and I myself wish you luck in this difficult task. We are all waiting for your long-awaited accepted balance changes.

Also a lot of foolish ideas.
And I will remind you that Eagle Eye is primarily a mage ability, while you want to turn it into artifact peeking. I think Eagle Eye should not be changed that way, but simply made more useful and effective.

A decent small change, but I liked another participant's idea better: give the ability to choose 1 of two stats, which will let a mage more often manage to choose Attack or Defense instead of Spell Power and Knowledge
In general, I sometimes think Knowledge is a weak parameter; often people do not take much of it. Everyone leans into Spell Power. I previously thought that Knowledge specifically should be able to extend debuffs and buffs, though I also do not know...

why?
why again
and why again?
Why make Frost Ring a copy of Meteor Shower? By the way, a couple of ideas about Water Magic were suggested above.

I am against making Water Magic something expensive and very sturdy; that is a lazy solution. I want to preserve its idea: a cheap, simple spell, like a soft stream of water flowing down the hand

though the fact that I am against it concerns no one; I cannot forbid it.