HotA - General Questions and Discussions

Resistance is not only the ability to resist something, but also a physical quantity that weakens the current passing through a section. If we apply this analogy to magic, then reducing the power of magic seems quite reasonable (we can imagine that each hero has his own magical channel through which he affects magic on those around him, and the opponent may be able to worsen it, increase resistance there). I note that artifacts for resistance in the English original also have "almost physical" names — Garnitude of Interference, Surcoat of Counterpoise, Boots of Polarity, and the new property suits them even more.

Nevertheless, changing the name and icon of the skill in some form is quite likely, since the correspondence to it in the new version is still weaker than in the old one, and this bothers many. And it goes without saying that the new version is connected to the old only by the fact that they both counteract magic, so there is no need to apply the logic of the old version to the new one.

It was interesting: when attacking fairy tale dragons with resistance, does their SP decrease? Or do fairy tale dragons not have spell power?

It clearly follows from the description that it does not decrease. But I can "reassure" you — the original resistance does not work on them either.

It is clear that they wanted to make a percentage reduction in damage from magic instead of complete reflection, they took the path of least resistance (it is easier to reduce SP than to reduce damage from combat, for this you have to dig deeper).

Nonsense. Perhaps such an approach was practiced for WT — I don't know, but this is not typical for HotA. In this case, exactly what they wanted was implemented. In particular, they wanted to weaken resurrection and summons. But Armageddon on its own — there is no need for that. In addition, it is easier to implement golem resistance than to reduce spell power.

And everything is logical with the Lizard, if the units resist magic (and resistance endows the hero's army with the ability to suffer less from magic, and not debuffs the opponent's hero), then it doesn't matter what its source is, the damage should be reduced, period.

The old resistance endows its own units, the new one debuffs the hero. Each of them has its own logic. If it was decided to completely change the property of the skill, then there is no particular reason to tie to this detail — except for the correspondence to the name and icon of the skill, as I wrote above — their change is quite likely.
Well, the option "Reduces SP + reduces Armageddon on its own" still does not fit into any logic.