By the time they eventually get round to 'X4' Patrick Stewart will be in his 80's. Hugh Jackman will have probably moved on from Wolverine, so Halle Berry will likely be the only lead interested in returning. Anna Paquin may return if Rogue has a good role, so I can see a scenario where Storm is leading the school with Rogue and Iceman (possibly Colossus) as teachers. Plus new characters who have joined over the years. Anyway, back onto box office competition.