The recent post from Holinka released the time Blizzard would like to keep seasons going for, which is 20-25 weeks. Considering that season 14 started on September 3rd we would more than likely see the new season start on February 24th at the lasted assuming it will last 25 weeks. Season 15 will more than likely be with patch 5.5, so we can expect to see the goodies with that patch no later.
* At 20 weeks 5.5 would come at the earliest of January 20th
https://twitter.com/holinka ( Holinkas twitter for those that want source)
As for WoD, if Blizzard were to keep with this model we can expect it no sooner than June 20th and no later than August 26th, assuming they'll give a week between seasons.
Although I believe this is a good perdiction, it is an alarming one. In my honest opinion nine months of doing SoO content and the likely small patch of 5.5 between the expansion would get old fast, and I don't believe I'll be subscribed for the majority of that time.
What do you guys think of this?