I don't necessarily think this is a case of that though, I personally feel as though for the last ten-fifteen years there was a lack of interest by Marvel to really push the X-men, and while they are willing to go out on a limb. It's just usually in a contrived and unnecessarily complicated or regressive manner. Sure we've had several highlights/takes over the years like your Carey, Gillen, Remender, Taylor, Thompson, and a select few others. But with WATX specifically I felt it did a disservice to the characters involved the teaching staff were irrelevant save for Logan, Quire, and Kitty. The stories did mostly nothing to advance the characters narratives' beyond the issues themselves, and a lot happened just to happen with little to no follow up. Were there good issues sure, but that was usually proceeded or followed by not so good issues.
That and when you compared what Gillen had been doing in UXM, he just seemed to have a better grasp of his cast, that and I'm personally over writers introducing hundreds of characters in a series only to be forgotten at the end of the run. Has anyone seen, Warbird, Broo, or Gladiator kid since, how about any of the supporting and the developments they received?