I tend to agree they should be separate, but more just for narrative reasons than anything else. The thing is, superheroes are supposed to be special. Sure, there are quite a few of them around, but they're rare compared to ordinary humans and there tends to be a unique reason they are super - bitten by radioactive spider, hit by lighting in a lab, hit by radiation in a different lab, absorbed alien power, found magic ring, and so on. The problem with mutants is there are too many of them and they're all basically the same. Different powers, sure, but everything boils down to "I'm yet another mutant with whatever powers the author happened to want" rather than "I'm superfast because I was hit by lighting while sciencing and lighting is fast so it's all perfectly logical and different from other heroes who didn't get hit by lighting".ShirowShirow said:I always held the assumed to be controversial opinion that the X-men should remain seperate from the rest of the marvel universe in all its forms. The "Powered people as stand ins for marginalized groups" metaphor works better when there aren't a whole ton of other powered people running around...
Basically, the X-Men spoil all other superheroes and villains by being too common. There's nothing special about having powers when there are hundreds of other people in any given town with exactly the same powers, and a bunch more with others. When it comes to film in particular, note that the X-Men films have very much focussed on mutants being extremely common and the issues that raises for society, while the MCU has focussed on superheroes being very rare - there are only two heroes with actual superpowers (Hulk and Thor; Tony Stark is a regular guy who builds robots and Cap is supposedly just the peak a regular human can reach), and one of them doesn't even live on Earth. Even if they can come up with a way to introduce mutants as a new thing (cosmic event causes mutants to suddenly start appearing or whatever), there are two mutually contradictory approaches to superpowers.