EDIT: I'm an idiot, I should've put this into the Warlords of Draenor general discussion... and that's why I didn't see a post like this because I was watching the General Discussion forums, not the WoD general discussions...
Next PvP season will probably start on February 18.
So they would probably release WoD on July 15.
Worst release time ever, I think.
So they probably release it on June 24 or 26 to make it in the second quarter.
I think these dates are pretty much accurate because of this:
Anyway I wonder how many people will stop playing between now and july. No new content for 10-11 months.