Yosemite made me do it... join these forums, that is.
I'm very disappointed in Yosemite on my 2011 iMac. I have 32GB of RAM and a 1 TB SSD...I shouldn't have any difficulties and for the most part I didn't. However, over the weekend I reverted to my last known good install of Mavericks because every time I tried to play WoW, the graphics were so choppy and stuttering so bad that I found it to be unplayable. The game (patched to 6.0.2) runs smoothly on Mavericks, but it stutters and it's choppy on Yosemite for me. It almost resembles network lag. The funny thing is that I would be walking around in-game and supposedly I would have 80+ fps but It seemed like I was more around 15 fps.
Although I've read from many others that they have had no issue with WoW on Yosemite, I have seen a few that mentioned the same or similar issue. I'm not quite sure what the issue is, whether it's a bad video driver or what. I noticed this issue back in public beta 5 and submitted it through the feedback assistant. I did the same again in public beta 6 and after the official release. Maybe they'll get around to fixing it in 10.10.1.