My predictions: (some I'm going out on a limb on)
- no new class or race; agreed that this selling point will be updated models
- new xpac area will either be Outland or some other planet in twisting nether. May have Azshara's area as a zone to conclude N'Zoth stuff
- Hearthstone in WoW will be the dance studio of the xpac
- WG or AV-ish area will be combined with Timeless Isle approach for one end-game zone
- 10 man or normal mode raiding will be axed. (This is out there IMO)
- an invasion world event triggers the reason we go to Outland 2.0
- warlocks get a class specific, legion-based flying mount
- kil'jaeden dies this xpac
- Draenei and Velen take center stage in this xpac
- we meet and possibly fight our first Titan (they are more cold toward us like the dude was to humans in Prometheus)
- timeless isle and battlefield barrens gets over-fucking done this xpac
- wrathion upholds his fathers purpose but in a nearly cold ambivalent way that sees a major alliance casualty (varian) against the legion, stopping a plan to destroy Azeroth