I would say too that the AI is better and smarter, but weaker perhaps because of pioneer thingy.
Two things I noticed that felt wrong:
Strategic AI: The AI sometime move around an enemy outpost, probably because its goal is further away, whereas the more sensible move would be to move over the outpost and then proceed. Perhaps a test on each stack, if adjacent to an enemy outpost (so no pathfinding involved here, a real time save), switch the first movement leg to take the outpost then continue to previous goal.
Tactical AI: AI hero, alone, facing 6 units of pikemen and my fire archmage sovereign cast ... Protection from cold (and I had no possibility to send cold spells either!).
More specifically, 'protection from' should never be cast randomly but should make sure the enemy has some significant damage dealing possibility in said element.
easier said than done, I know.