Races i would like to see are Githzerai and Aasimar, and vHuman.
Subclasses i'm mostly fine with, Grave Clerics are cool, and i really like Circle of Stars druids.
Not knowing anything about Githzerai, I looked them up and wow, yea, that would have been incredible as a contrast to Lae'zel and the other Githyanki in the game.
I have 0 idea why they didn't have a Gith Race and just make the yanki and zerai subraces. On a good note that is going to be one of the easiest mods to make.
The only thing I can venture a guess about the reasoning is that they are basically KoS for each other, so they didn't want to have to deal with a whole chunk of act 2 being completely unusable because you picked the wrong sub-race.
So I guess I have 1 idea...