I agree – it's unfair when one hero's special ability is unusable in most cases, while another hero's ability is always applicable (by the way, I think Direal and Leto are also disadvantaged – their special ability doesn't work against the undead).
Added 1 minute ago
How about this special ability:
If a hero's knowledge increases, their spell power increases by the same amount.
Perfect for an Academy hero.
ColouredText - список заклинаний и их уровень в описании существ-колдунов