I am for subraces as they are a way to rip culture out of the genetics of race. You get the base race and if the DM allows it, the subrace culture. So you pick elf and at "wood" culture on top of it.
And I am only for "mostly" culture subraces. No ability adjustments on subraces.
I think that is what they are going to do. Also, must spread xp around.
@ up: it is possible that subraces will be background.