I wrote this a year and a half ago and mostly stand by it. I think its the perfect way and I think it is somewhat close to how they'll do things.
"I actually think I have a solution that makes everyone happy and solves a LOT of the problems the X-Men present as a film franchise. We start off with an established X-Men, just as we did with Spider-Man. No need to introduce mutants as a concept, just where they've been which we'll do throughout the movie instead of in a big info dump at the start.
Have the movie start with Xavier calling a big group of classic X-Men into his office. We have Cyclops, Jean, Iceman, Angel, Beast, and for good measure Psylocke and Nightcrawler. They've all been X-Men for a number of years and comprise most of the senior team. Xavier thanks them for all their hard work, mentions the great job they did stopping Magneto (or another big villain we won't see anytime soon) recently and then tells them they're fired. They freak out but he explains that the X-Men aren't just a super team but a part of the school and new opportunities need to be given, both for other more senior members to lead, and for young mutants to get their chance. They ask where they're supposed to go and he tells them wherever they like.
We're then introduced to the new team. 7 members. Enough that it feels like an established part of the school, but not too huge that you can't focus on everyone. Storm's the leader but the rest of the team includes Rogue, Gambit, and Colossus as the established group. You then have the young group getting their first shot who will be Kitty, Armor, and Warpath. (I also considered M and Husk and neither would be a terrible choice) The movie focuses on these 7 and not Professor X who is a tertiary presence. He matters, but he mostly leaves the day to day leading to Storm.
That's the team. Kitty/Storm, Rogue/Gambit, Colossus/Kitty are all classic relationships to build from. Avoid Wolverine at least for now, he'll suck all the oxygen out of the room from these other characters. Maybe a brief mention of Logan jumping before he was pushed when the original group leaves to establish that he already has ties to the X-Men if you don't want him to be a new character to them when he finally shows.
This gets to have it both ways. You just established 7 huge X-Men characters, including that original 5 with a couple of additions to diversify the group and then threw them out. Right after this movie you announce an X-Force movie starring that group striking out on their own. People who want the newer characters get them. People who want the O5 with a bit more diversity get it. Psylocke seemed a natural addition to that group with Warren being there. Here we still get the strong leader Cyclops and get to really establish that group.
The X-Men have way too many good characters to contain them to one team of 5-8 people. There's a reason there are like 6 X-Men teams in the comics at any one time. With one team in the movies you'll end up with the same issues Fox had. Either you have way too few characters and fan favorites don't show up for years, classic character interactions no longer work because of the differences in age/seniority this creates and it doesn't feel right to fans. Or you stuff way too many characters in and tons of them feel like they're not in their proper roles or are background characters which is no more satisfying. One of your yearly release spots can go to an X-Men movie. If needed Marvel can crank it up to 4 releases a year to accommodate this. With Fox gone they have less superhero competition in the marketplace, making this more practical. Each one has a two year cycle though because of two different teams we cycle between. If you want an extra year now and then you can even stick a solo movie into that slot here and there. Plenty of X-Men characters could support it. You also have the option to have the two teams butt heads or team up against a greater villain. Characters can swap teams or move in and out as their schedules allow to make it more attractive to some actors as well. More potential big crossovers are not a bad thing to Marvel anyway."
The only thing I'd add compared to two years ago is that now you have Disney+ in the mix. That's more room for solo projects (maybe start Wolverine there if you want to get right to him but not suck all the life in the movies toward the character). I also think they'd be crazy not to do a young mutants show. Like Generation X, or the school characters from the Astonishing run like Glob Herman/Beak/Anole/Rockslide/etc. Seems like a no brainer.