The following contains spoilers for the ending of Split. If you haven't seen it yet, you really should do that before reading this.
If you've seen Split then you know the movie opens itself up to possible sequels. James McAvoy has already been part of one major franchise, is he really that interested in another? The man who plays Professor Xavier in the X-Men films says that he's really just interested in making good movies, and if that means getting involved in a franchise that's fine.
If it's good material, I don't mind if it's a franchise. If it's good work and I'm getting to work with good people and I'm getting to do interesting things with my day then, yeah, I'm bang up for it. I don't care if it's a franchise or not. I'm all up for a good old franchise if it is a good old franchise.
For those of you who have seen Split or have unfortunately already had it spoiled for you, you know that Split is, in its own way, a continuation of an existing franchise. The last minutes reveal that Split takes place in the same universe as M. Night Shyamalan's superhero drama Unbreakable. The film seems to pretty clearly set up a potential encounter in the future between Bruce Willis' David Dunn and James McAvoy's Kevin Wendell, aka, The Beast. M. Night Shyamalan has specifically stated that it is his intention to make a third film in the series at some point down the road. McAvoy tells The Hollywood Reporter that he didn't know Split's connection to Unbreakable when he began filming, so the franchise expectation certainly wasn't there, this is the first of the writer/director's movies to see any sort of sequel, but clearly he's up for it if and when the next movie happens.
It's amazing how much things have changed in the movie industry over the years. It wasn't that long ago that many actors actively avoided "franchises" for fear of being typecast. It was an entirely valid fear, as actors like Christopher Reeve and Mark Hamill never seemed to get much work following their roles as Superman and Luke Skywalker. However, today franchise moviemaking is so big that it seems to have overcome the typecasting idea. Many actors are part of multiple franchises, and as such, they never get stuck with a single label. This means they can focus on just making movies they enjoy making. The fact that many of these franchises tend to pay well probably doesn't hurt either.
The good news for fans is that James McAvoy is willing to make as many of these movies as it takes as long as they stay good. As fans, we certainly hope they do too.