After 0.04 in order to unlock the new abilities your hero must have points in specific skills, like King Bounty:Legend Training skill, only expanded to more skills.
For instance in order for your priest to have cleansing flames you must buy Power of the Spirit skill level 1. The requirements are stated in the readme, but you can also see in the skill tree, what additional abilities that skill unlocks.
For example if u check skill Trophy, you'll see that it teaches Mercenaries the Search ability
Heroism teaches Guardsmen and knights a few thing, Alchemy teaches assassins to use the almighty acid flasks and so on.
As for the difficulty, i agree most of the monsters become a lot harder to battle, i think hard difficulty its actually hard now, and impossible seems...well impossible
Still need to playtest and balance though. Thats why feedback & suggestions are extremely valuable.
For now though i moved to a new pc
so it will take a few days to resume the development process.