@Baardvark
It doesn't stack.
On a side note I don't really like that ability. Every others racial are something unique that only the character benefits from. Human racial cost 1 ap for the character and gives a bonus to everyone. Since all your party have it, it doesn't feel unique, for me at least.
Beside it was a warrior skill in DOS 1 and now it's for human only ? Meh.
I'm not saying it stacks (with itself, as when another human casts it, you mean?), I'm saying it scales. I'm not sure how much, but it should be at least +3 per stat by the end game, possibly more.
I agree it's not very exciting. But it is decent.
