Xavier is the most powerful mind in the universe
Then how did Stryfe so savagely own him?
Cable is a very cool character, Bishop less so, but I don't think they'd affect much. Cable has to exert most of his energies keeping the techno-organic virus at bay, so he can't do much else.
All of Marvel versus all of D.C. would probably end with Marvel winning because of all the cosmic entities, except that D.C. has established the existence of a supreme being that would trump even things like Eternity or Galactus. This being has been portrayed as a character, oddly enough, in the Lobo's Back series, so I say He counts. :shock: