I think August is the right timeframe to look for WoD. This gives Blizzard a launch window for D3RoS, so that they can get that product out and clear their production pipeline to QA, market, and release WoD.
At some point, they will probably start nerfing raid content too. They like to make sure everyone engaged in raiding is gradually moving forward, no matter where they are. WoWProgress has some pretty neat stats on this:http://www.wowprogress.com/stats
The number of new kills on heroic bosses slowed down greatly between Dec 16 and present. Now obviously some of that is due to the holiday break messing with raid schedules, but it's also possible that many guilds are close to reaching their final progression point, as we are all reaching the point where gear is pretty much capped. I estimate lot of guilds will never be capable of killing Thok or Siegecrafter with the current balance--they're legitimately hard fights.
So it remains to be seen whether the graph will pick up the kill rates seen in November, or whether they will remain dampened. Once they do slow down, Blizz will probably institute small nerfs to keep people moving forward and paying subscriptions rather than wander off to other games.