Heroes 5.5 WarGame Edition - Tactical Edition.

You're suggesting increasing the cost of the rune – by approximately how much?

I haven't decided yet. First, I'll consider the possibility of removing the rune altogether. And then, perhaps, I'll try to reintroduce it at different prices and see how it affects the balance.
We're talking about the dragon rune. Firstly, it's buggy (for some reason, it doesn't work on dragon upgrades, but it does work on the base unit). And secondly, in the context of the mod (with its powerful stats), it's overpowered: for top-tier units, it's equivalent to a 400% increase in damage and survivability. In the original game, it was only 200-300% for titans and basic dragons.

Added 1 hour 5 minutes ago
I've updated the information on classes and skills in the first posts of the thread. Information about creatures and magic will be updated later, before the New Year (when I finish implementing them).

Regarding the dragon rune, I've done some calculations and it turns out that everything is fine; the actual increase in damage and survivability will be within 250% (but at the same time, the rune will be useful for a wide range of units, unlike the original). So, now the priority is perhaps just increasing its cost.