Githzerai, because I think they are at least ten times cooler, than githyanki, if you would play planescape torment you would know...

Although I doubt, that they would go crazy adding a lot of monster races, as I think they are a lot of work. Maybe with some shapeshifting or modded items, you can play around with different avatars at battles...
I am quite happy already, that they have drow,
if they would have originally planned Githzerai as playable race next to Githyanki I would be already very-very happy for the game, hoping to get my first physical copy of my collector s edition, as soon as possible if they have.
