Yes, clearly we don't need subraces to enable us to create humans that look however we wish, so the only reason for subraces that I can see is that we might want humans that have different racial abilities. And given humans are set up to be versatile by definition, I don't see any call for that, though admittedly I'm not a 5e expert. But from what I do know, either the PHB +1 to all abilities human, or the variant human with the adjustable abilities plus a feat of choice have all the bases covered. (I'm not going to take a call on Larian's homebrewed version until we get some very definite info on it!)
So, on the assumption that variant human isn't really a subrace, this gets a no from me.
