Seeing how FFXIV ARR was build around low end pc i think it would help better load times and such. But you wont see much different if what they say the engine can do is right. For 1.0 people said it made a hell a lot of different but i guessing that due to the shit engine crystal tool was not build around for mmo.

Having a SSD in ARR i see better loading when going to zone to zone and loading npc/char better. Not sure if you see much of a different tho but it helps