I've been advocating for years for a weekly X-Men book to be published alongside a couple of spin-off books at most, to replace all those satellite titles that struggle to get to issue 20. A mix of a single creative team working on the same issue/story and multiple creators working on the same issue, with the focus shifting across multiple stories and characters every issue but with an overarching story to justify having everything in the same book. The blueprint being DC's excellent weekly series 52 from the early naughties.
You basically do SWORD and X-Factor etc but you call it X-Men. A lot more coordination would be necessary from the creators and editors but obviously they'd enjoy higher sales by virtue of being condensed into the same flagship book.
I believe the reason why Marvel has always shied away from this kind of endeavour is that the uplifts and press they get whenever they launch a new X-book is a short-term gain they're too attached to, but longer-term I strongly believe it would benefit their sales immensely.