Never had any issues diverting for weather over China. In fact, at least in Beijing airspace, they have been quite proactive in vectoring around weather on arrival and departure. Once, declaring a low fuel situation as a result of and unexpected hold with no EFC time, vectored immediatly direct to PEK and then they flipped the landing runway to accommodate us.
OTOH, Japanese controllers can be quite obstinate. Requested direct to the oceanic entry point, bypassing the previous one due to weather. Never approved despite a few requests. OK, then proceeded to that waypoint I wanted to avoid, but then could not proceed to the oceanic waypoing as a build-up was in the way, and the controller was then going ape-**** because we were proceeding into oceanic airpsace without clearance in that area, unable to turn. Finally had to fly through what I didn't want to fly through and I relented because the radar returns were yellow at altitude. Secured the cabin and got some moderate chop. It seemed to be me to be a pissing contest, as the controller probably figured I wanted to cheat and take a short-cut, using weather as a pretext. Not very professional at all. Chinese controllers sometimes have difficulties with language, especially en-route, but nevertheless found them to be professional.
I expect that the controller responsible for the Delta incident is heading off to the salt mines.