Is there any reason the AA is limited to Elves or Half-Elves? Is it just a "flavor" thing? I just can't see how allowing other races to be AA's is unbalancing. Anyone have a solid argument for limiting the races that can choose AA?
Same reason only a Dwarf can become a Dwarven Defender. One could easily just call the class Defender and allow anyone to take it. It's strictly a flavor thing.