3.4 will probably be somewhere in early/mid Sept to play with Legion which is end of Aug, maybe a bit earlier if they really want to compete. After that with a 3 month dev cycle 3.5x will be around dec/new year or right before JP fanfest which is at the end of december.
That leaves the expansion maybe late winter or in spring depending on how long they want to drag on 3.5 like they did with 2.5x, or they could pull a wow and make us wait an entire year. Who knows.
Code:
2.0 8/27/2013
2.1 12/14/2013
2.2 3/26/2014
2.3 7/07/2014
2.4 10/27/2014
2.5 1/19/2015
2.55 3/30/2015
3.0 6/23/2015
3.1 11/09/2015
3.2 2/22/2016
3.3 6/07/2016