A Warrior hero from the Dungeon faction? That's absurd...

Yeah, a Warlock with only one Chaos skill isn't a mage, it's just a clumsy attempt to make a warrior.

I disagree. Even with a second school of magic, it feels wasteful to spend the hero's turn on buffs/debuffs or mind control/berserk when you can wipe out a crowd of enemies with enhanced Chaos magic. That's why I only level up Chaos for my Warlock.

A mage also needs Sorcery, Education, and Luck wouldn't hurt. And of course, Chaos:)

I agree with that. That's exactly what I level up. Also, Empathy, if I can get Leadership quickly enough. Otherwise, I level up Attack.

In the Stronghold campaign, my Elai was offered Leadership right after the first level-up. She couldn't refuse. She turned out to be a great elf. In the final mission, she single-handedly crushed all the enemies in the dungeon with her starting army. She just didn't have enough time to capture the native castle. I played on the Hero difficulty in version 3.0.