^ Totally agree with a lot of what is being stated above...
Here are some things to think about...
We have five main stars in these X-Men movies, all of which will want, and likely get a lot of screen time.
The five I'm talking about are:
Xavier
Magneto
Lawrence
Jackman
Hoult
So far, in this First class movies, we've seen, as I explained above, the struggle between the two sides of the coin, Xavier and Erik, with Mystique stuck inbetween. Yes, we saw her doing her own thing in DoFP (saving mutants), but that was because, as we found out, Erik left (and was imprisoned).
But we have to know that they need to conclude the Erik/Xavier tug-a-war of Raven story.
At the same time Xavier has been given a different mission. His task is to find them and bring them together. This is where we'll get to see/meet Scott, Jean and Ororo, and possibly even Kurt (I hope).
Now, mentioning Kurt, if they stick to the concept that he is Raven's son, that would almost have to play into this story. Think about it... If Kurt's father is Azazel (and if they change that I will lose all respect for them) then what caused Mystique to be with Azazel? Erik left her, and she almost certainly has anger over that. So did she seek confort in the arms of Azazel? Or did he force himself on her? Or did he trick her by pretending to be Erik? Whatever it ends up being, the point is that Kurt was born due to this, and what did Mystique do? She abandoned him. I would imagine that Kurt would have problems with that as well. I could see a very emotional scene between Raven and Erik with things like "Why did you leave me?" and "I loved you". Things like that... Then she could explain the whole Azazel and Kurt stuff. That will be crazy powerful, if they go that route, which I truly hope they do... I could also see it being Charles, through his powers, that discovers the truth about Kurt's parentage and either drops the bomb or confronts Raven and guides her to revealing the truth... Again, powerful stuff...
For Erik I can honestly see him having come to the conclusion that taking over the world is not the right way to go. I could see him being isolated, and looking to start a country or at least a place where mutants can be free. This is the story of Genosha or Avalon or Asteroid M or Sanctuary. This would make total sense, if you think about it. I could see Erik going to the X-Men, who would possibly think he's attacking (short battle ensues), but ultimately Erik would invite them to go with him. Most would, of course, say no, but I could see someone like Quicksilver, if he's with the X-Men, joining up, especially if it is revealed that Erik is his daddy.
I'm starting to see this theme of parental issues...
This type of storyline could lead to the next movie with Magneto as a true villain (being affected by Cortez).
Beast's character is really supporting. There is no him and Raven stuff, so they shouldn't force it, though my guess is they will. Yes, in First Class, way back in 1963, there was this attraction, but that was 20 years ago. Bringing that back to the forefront would come off as trying to give Beast a story to resolve. Look, Beast's story is simple. He's supporting Charles in making the school a reality. He should be nothing more than a mentor/instructor for the X-Kids, and obviously he would be in the inventor role as we've seen in the last two movies. He can invent the Danger Room, new uniforms, Scott's visor, etc. Yes, he would likely be present during battles, but he's not the field leader, and more than likely the writer would take steps to force him away from the X-Kids during the battle. Maybe something along the lines of his skills being needed to amplify some piece of equipment, or inventing something that would disrupt the control Apocalypse has on Wolverine, or something like that.
Now Wolverine is the toughest one. Mystique took him for a reason, and we all assume that we'll have to see him get his adamantium back in this one. IMO, making him a Horseman (per the thread I started a year ago) makes the most sense. It gives a reason for him to get the adamantium back. But further it allows the movie to not be focused mainly on him, as we've seen movie after movie after movie. Look, Wolvie is pretty much the coolest character out there, but at some point you have to cut the chord, or at least allow the focus to be elsewhere. Making him the villain, via control (he's a Horseman) keeps him in the movie, resolves the things that need to be resolved (he gets his adamantium back) and makes it so his character doesn't need to get all of the attention/development. It'll also give the audience, and Jackman, something they've never had before...
I think to take all of this further you need to ask yourselves these simple questions:
- What has/is Xavier doing?
The answer should be finding and bringing them together. Effectively the school.
- What has/is Magneto doing?
Lots of ways to go here, but I could see him having isolated himself with plans of creating an Avalon for mutants.
- What has/is Raven doing?
Seems like she would have continued trying to save mutants. Would she form a team to do that? What did she do with Wolverine?
- What has/is Wolverine doing?
Who knows. This all comes down to Raven's purpose of saving him. Ultimately it'll lead to him getting his adamantium back.
- What has/is Beast doing?
Most likely helping Xavier and inventing more stuff for the mansion.
- What has/is Scott, Jean and Ororo doing?
Makes sense that they have been, or will be found and brought together by Xavier and training/will be trained at the school. That means seeing them in the Danger Room.
- What has/is Quicksilver doing?
Tough one. Did he continue to live in his mom's basement? Is he a professional criminal? Did he join up with Magneto? Did he join up with Raven? Did he join up with Xavier?
- What has/is other mutants, like Havok, Toad and Ink doing?
Maybe they won't come into the story, but I have a feeling they will. These guys are not leaders, so if they are part of something it'll be as followers. Would they join with Xavier? For Toad and Ink the likely answer is no. And It's hard to see Havok continuing in that life. I could see Toad and Ink joining with either Magneto or Raven.