Morrison and McIntyre I can definitely see as future champions, and probably within the next 2 years. They both have 'world champion-like' characters if that makes any sense. Morrison is the flashy, charismatic, Shawn Michaels-esque champ, and McIntyre would make a good, ruthless Triple H-like world champion.
As for the others, I can see Christian winning it within the next year, but I can't see him holding it for a very long time. 2 or 3 months maybe. Kingston I could see if they put him in a few more feuds with main event level guys like the one with Orton last year.
Miz, DiBiase and Rhodes perhaps, but in at least 2 or 3 years.
Truth and Hardy.... I don't see it. Then again, who knows with the WWE?....