As you have heard, another leak was posted and immediately deleted from reddit, apparently posted by a Blue who was laid off by Blizzard.
The main Points are-
FINAL EXPANSION OF WOW. After this, Blizz will be making a new MMO, possibly based on Warcraft and an entirely new engine.
Main Antagonist-Sargeras
Zones are twisting nether and Argus
Velen returns
Sargeras kills archimonde for failing, recruits a new successor
New Class- Demon Hunter
illidan returns
Ki'l jaeden will be first raid tier
Gul dan is killed of early as well
Neutral Titan Faction-with Algalon playing a role, having seen us before on Ulduar. Tyr absence explained.
Path of the Titans returns
No more Garrisons
Confirmed twisitng nether is one realm
Thrall is killed by Sargeras
Mercenary option combines both factions for LFG
Lots of well known heros die off
Blizz was not happy with the current engine and feels the game is obsolete.