I think it all depends on the actual execution of said content. What I can assume at this point is that the "razorpax" idea about a dragon-based expansion and a dragon knight class that is closer to the Titans than anything sounds like the epitome of generic expansion concept.
https://www.mmo-champion.com/threads...9#post51733779
MoP had great mechanics, beautiful areas and good storytelling. However, that didn't exclude the fact that the place and Pandaren were way too whimsical and Monk pretty much took the spot of Demon Hunter like the first Monk NPC jokes about.
Given all the foreshadowing, this is the best moment to add a Shadow/Death based expansion and a class related to that. Sidetracking the expectation to a Dragon Isles filler with everything Shadow/Death related as a B plot sounds like a curveball to me.