And non-Wizards don't need Intelligence. And technically, you can avoid needing Constitution at all for most of the game. I didn't put any points into Constitution until I reached the high 20 levels.

I see what you mean. Rangers only need Agility for their bows and Wizards only need Intelligence for spells. A Warrior could use only Strength for melee. I think this is just going to cause over-specialised characters. I'd much rather see a requirement for all attributes in each class.