I personally would like to see the X-men film-o-verse become part of MCU canon, but only one timeline... I liked that they were rebooting using time travel, rather than just a do-over. Problem is, they screwed thats up too.
So... the original timeline would be canon, which would include everything up to 1973 (so First Class, flashback scenes of X-Men origins Wolverine, other good past events, like Magnetos WWII scene as a boy). Then, the time change by Wolverine in DoFP puts us on the current MCU timeline, which should include Deadpool and any new/different X-men films to come (New Mutants, X-Force, rebooted X-Men perhaps).
The idea is that Apocalypse and Phoenix are actually in the same timeline as X-Men, X2, Last Stand, X-Men Origins modern scenes, and the future scenes of DoFP. When wolverine goes back to 73, those other movies go away and everything is nice and tidy. That way, MCU canon can include the cool stuff (First Class, Liev Schriber as Sabertooth, the WWII scene with a young Magneto, Quicksilvers Pentagon scene, etc).