Hardware anti-aliasing doesn't work in deferred shading. FFXIV uses deferred shading to make dynamic lighting very inexpensive and scale well.

http://en.wikipedia.org/wiki/Deferred_shading

"One more rather important disadvantage is that, due to separating the lighting stage from the geometric stage, hardware anti-aliasing does not produce correct results anymore since interpolated subsamples would result in nonsensical position, normal, and tangent attributes."

MSAA and family are not options because the renderer does not allow for it.