I am pretty sure that WoD is *full* to the brim of things that you can use to make testable predictions.
For example, MoP featured the farm as a testable prediction: that players would use it, and enjoy it, enough that it saw significant playtime. It tested true, and we get garrisons in consequence, which are doubtless filled with testable predictions about what people will do and enjoy with them. WoD+1 will feature, well, features based on the lessons learned.
Ditto the healing approach, which is definitely a testable prediction: that their model of "cata triage healing without fucking up mana" will be compelling gameplay.
MoP featured the testable theory that active mitigation for tanks was awesome, and WoD sees that finish: all tanking is active mitigation tanking now. That one tested true with the playerbase.
...and on it goes.
(Of course, masternewt actually meant "WoD is bad, and you should feel bad", but whatever.