I say take a break, do some hardcore reassessment, and bring in a new creative team. Abandon the time jumps. Focus on the young X-Men, and stop emphasizing the Xavier V. Magneto conflict so much.
It's not just one disappointment. It's 3 films with X-Men in the title within the past ten years. This particular film will hurt the next film called X-Men significantly, even if it gets high reviews. It is going to have to work it's way up again unless it looks or is called something completely different. Even DOFP's success and positive reaction wasn't enough to help Apocalypse.
This is just as bad if not worse then ASM's situation. The only positive light is Deadpool's success will keep it going with confidence. The main IP needs to switch things up, they have no other choice.
Like Drew McWeeny said, X Franchise is a unique situation for Fox.
ASM 2 was a sequel, second part of trilogy so they were f***. It was difficult to continue with the hate. Whereas XA is conclusion of sorts to the second X-Men trilogy and the beginning of new era. It would have been problematic if audience loved Xavier/Magneto/Mystique and hated the new cast in XA. But, it's the opposite.
Before BVS, Warners said DCEU will be dark and gritty but they changed plan and bring Geoff Johns. It is 180 degree.
Before XA, it seems the plan was to developp others caracters with spin-off and focus on then main team with more colorul costumes. So, i dont think you will see big change.
If you look others project (New Mutant, Deadpool 2, Gambit, Wolverine 3) you have producers Kinberg/Donner and differents writers/director.
So i think it will be the model for the next X Men movie. XA US BO could be disappointed for Fox but they have a lot of possibility two and it is new for them.
Drew McWeeny s' video is very interesting
http://www.hitfix.com/motion-captured/review-x-men-apocalypse-should-please-fans-but-its-awfully-familiar-fare
"I think they have a lot of option on the table and that they wanted"
"Tom Rothman 's vision was small and thx Kinberg/Donner/Singer all the option are on the table"
ASM wasn't in this position at Sony. They have the right plan but they should just make the right decision for the future.
The big question is Singer, he wants a break but after XA, i don't think he wants direct anymore or soon.