I really, really don't like the stat bonuses being tied to backgrounds. This is, in my opinion, a serious mistake.
There was this ... discomfort, this tension, with stat bonuses and class. If you played a "dex class" but your race was dwarf, you were at a bit of a disadvantage for example, because you didn't get to boost your main stat.
Shifting the stat bonuses to the background just re-creates the same problem in another place. I want to play a cleric, but I didn't grow in a temple, I was a criminal before my PC "found god"? well, that's a wisdom bonus I'm not getting.
so instead of race choice being somewhat constrained, now backgrounds are. There was an opportunity to fix this problem, and instead WotC just moved it around.
edit: also why are specific languages tied to specific background? If you were a guard you knew dwarf? Why?