Joe is the most obvious candidate, since he has three of the titles already. But I think it's worth looking at some others, just to be complete.
First of all, given the current regime's treatment of the X Division, I don't think any former World Champions are going to be picking up that title, and I don't think anyone TNA management sees as a future World Champion will be picking up that title. So we're looking at guys who have already held the X Title and the Tag titles.
Kazarian--At first I thought, too old, but he's only 33. He has time to win the TV title and then the World title, but not any time soon, since he's AJ's backup in Fortune.
Doug Williams, World Champion? I don't think so.
Homicide--Maybe. They're trying to build him, matching him with Jeff Hardy and keeping him away from an LAX reunion. Sooner than Kazarian, but I don't know if TNA is around long enough for Homicide to win two different titles.
Eric Young? IF he does, he will win it on TNA's farewell show, Tommy Dreamer-style.
Jay Lethal--they think they're building him up with Flair, but they're not. Next.
Alex Shelley and Chris Sabin--they're invested in pushing the Machine Guns, so MCMG would have to run its course, with one of them still keeping management's favor, and then win both heavyweight singles titles.
OK, so my money is on Eric Young.