There are people complaining that it will break things because it's binary, that they can't have mandatory encryption, and that it's just too complex to fit in limited resources. There are probably other complaints that I didn't see.

I've never read it in enough depth to verify those claims, but the response from the standard group is always "then use HTTP 1.1", what is as a non-solution as it gets.

SPDY was great exactly because it was not the standard, it was an extra option, available if everybody agreed to it. Call it HTTP 2, and it will become mandatory in no time. IETF calling it optional won't change a thing.