It’s really a judgment call more than anything else. In the case of the Vision, that would ultimately be up to me, and whether we had any plans for him in any of the AVENGERS titles that precluded him from being in X-MEN on a regular basis, and so forth. But also, if you’re writing X-MEN, the expectation is that you’re going to be using the X-Men and the huge family of characters that’s been built up there, at least primarily. So somebody like the Vision could come into the series if the situation warranted it, but especially given the premise of the book–that the X-Men are all members of a particular minority, mutants–bringing in a lot of characters who don’t fit that premise doesn’t seem like a really good idea.