A lot of people hate Matt Ward, mainly due to fluff oddities and "Over-powered" codexes. However, it should be mentioned that he HAS giving reason for the Blood Angel/Necron alliance and I expect that he will explain more of the oddities if he is given time. Also, all of the newer codexes are "over-powered", so I wouldn't worry about it to much. It's still a kick in the teeth that Daemons are utterly useless against the Grey Knights now though.
The Necrons are finally getting their own brand new codex (It's very Egyptian themed). The reaction to this has been largely positive. The fluff has undergone a major overhaul, the C'tan are now shards and no longer lead armies (I think).
The Dark Eldar have their own new codex too, and the army seems to be a glass hammer of sorts. I don't think anyone disliked this.
The Grey Knights got their own overhaul and there are stories in there that pissed a lot of people off. Such as the Grey Knights killing Sisters of Battle for their Holy blood to protect them or something when they're already supposed to be purer than DeepRiverRock. Also, their Chapter Master spends all of his time in the warp fucking up all sorts of Greater Daemons and he carved his predecessors name in the heard of Mortarion (The Daemon Primarch). Many also didn't like the DreadKnight, comparing it to a baby carrier (Google it).
There was a triple-hitter time of the year, where GW raised prices, declared that no-one from outside Australia could sell online to Australia and announced Finecast.
Seeing as the first batch of Finecast was ironically miscast, the fans were in an uproar over this. I'd never seen so many pissed off threads and topics on the Internet about GW before this occasion, so it was a pretty bad time.
I think that covers everything major...
Oh, and deep-striking Land Raiders for the Blood Angels.