And that's where you have to think outside of the comic and realize......TPTB in the X-Men editorial probably don't want them to get a lot of help from the superhero community. They want the story to be about the X-Men. They have have big enough cast to juggle without throwing in the Avengers, The Champions, Thor or whoever else you want to name. Plus you have to sometimes consider they have to coordinate with the creative staff for those other titles to see if you can use the characters.