EDIT: Bornakk says that the achievement will be replaced in the meta achievement with one that requires you to simply sign up for the Brew of the Month Club. And for those who doubted my psychic powers: Noblegarden achievements are being added to Long, Strange Trip.
Following the pattern of removing achievements that take a while to complete from the holiday meta-achievements, Blizzard yanked Brew of the Year from Brewmaster on the current 3.1 PTR. This means that anyone who was missing it now has yet another fair shake at getting their Violet Proto-Drake for completing all of the other holiday achievements for What A Long, Strange Trip It's Been.
I'm pleased that players who missed that one achievement can still have a shot at the big prize, but man, there seems to be an awful lot of meta-achievement caving lately. It just creates the impression that complaining about something will get it changed, and I don't think that's what Blizzard wants players to believe.
To be fair, it was physically impossible for Death Knights to get this achievement until sometime in 2010. This is a good change for them and I'm okay with that. And no, I'm not against Blizzard removing unfair achievements from reward-bearing metas. This was also the only achievement which was impossible to complete during the event itself.
We'll see if the pattern holds after people miss another impossible-to-miss achievement in the Noblegarden set.
Grats to those for whom this achievement change will make a difference, and early props for your purple dragon.