Kitty Pryde's phasing properties are an enormous screw up. Nothing matters in the X-Men world anymore. Don't like how things went down? No problem, just send Wolverine back to fix it.
How annoying is it when you read a story or watch a TV show and at the end it all turns out to be a dream? That's what they've done to X-Men. Nothing that happened in all those previous films we watched actually happened. That was a different time-line and none of that matters anymore.
Just trash those old Blu-Rays. That didn't happen.