Quick comments: Melee units are almost completely worthless in this game. Ranged and Magic are superior in virtually every aspect, as missing out on attacking an entire class of enemies (Flying) is a huge detriment. Anything the melee classes can do, the ranged/magic do significantly better.
Suggestion: don't allow scrolls to be repurchased after you've learned their talent. It's already burdensome to search through the talent list to see if you need the scroll, so anything to speed up that horrid portion would be grand.