No, there's just a time and a place for when they decide to do what. This isn't universal physics. It's not absolute. They may always be inspired, find extra time, you never know. It's an organic process. You shouldn't view this as the excuse they will never do it, it's the reason they haven't done anything YET. And Cata presented a lot of issues as a result of dev resources allocated in places much of the player base never appreciated or made use of. This issue is nuanced and has a number of important circumstances to consider. Never say never.
- - - Updated - - -
And as of MOP, WOW's team was larger than ever in it's history, they now have 2 simultaneous teams working on major and minor content patches, mixed with miscellaneous projects and the 2 next expansions being developed at the same time.