From playing, it seems like they could learn healing, all kind of damage spells, resurrection, etc. With unlimited camp and resting, recharge between battle isn't an issue. I'm not sure if they have addressed it yet, but it could be lore related for wizard to be this strong? I'm just wondering if it's working as intended or if it's something that will change in the final game. As a single roleplaying game, maybe balance is less important than lore.