The "air view" and "earth view" spells are too overpowered for their level; the map could benefit from objects with similar functionality.
The current situation, where everyone is obsessed with two spells and the entire game is built around them, doesn't seem favorable to me (and probably not to others either). Many ideas have already been put forward on this topic, including rebalancing the schools of magic and adding new control spells, but all these ideas were limited to changing the magic itself. So, here's what came to my mind: you can create competition for the control spells not only with new spells but also with new objects on the map. (Although the City Portal has been added to the game, the developers have probably already thought about this).
Creating an object that replicates the functionality of the Dimension Door spell would probably not be very reasonable, as there are already objects with similar functionality on the map – portals. If you increase the number of portals so that you can quickly reach any point on the map through some portal, the value of the DD spell will decrease naturally.
Regarding the fly spell, there is a beautiful and atmospheric idea – add a new object called "Pegasus Stables." This object will have quite a high value and will equip the hero's army with flying horses, allowing him to fly around the map for the rest of the week. At the same time, similar to ordinary stables, you can upgrade pegasi for free in the Pegasus Stables.
I also came up with two objects with completely new functionality, but they fit well into the game mechanics:
1) Summoning Portal. Unlike the dungeon summoning portal, which for some reason clones troops instead of summoning them, the external Summoning Portal will allow you to buy troops from all available dwellings and cities. When visiting the object, a list of available cities appears (as when using the Town Portal spell), plus a list of external dwellings.
2) Communication Portal. An object for instant exchange of troops and artifacts between heroes. When visiting the object, a list of all heroes in the kingdom appears. You select the desired hero – an exchange window appears, as with a normal hero contact. The object can be used no more than once a day.
Corresponding spells can be added to the fire and water schools. An option can be added to the template settings – the maximum number of casts on the adventure map. (It's strange why you can only cast one spell per round in battle, but on the adventure map – as many as you want).
All of the above will not only balance but also speed up the Gameplay, which is more of a plus than a minus. Another interesting point is that these objects will significantly reduce the need to build chains, which cause confusion (in some cases, even rejection) in the minds of new players, and in general, they don't look very good from the perspective of game logic and common sense.