At this stage of his career, Hardy shouldn't worry about becoming a World Champion & should just be happy with what he's given. If He hasn't become a major main event star by now, then he is never going to. He's in his late 30s, and I don't think he'll ever recapture the energy he once had. The time to make a main eventer out of him would have been 2005 with the whole Lita/Edge story. They didn't do it, and that's on WWE creative, but Hardy's sunk down the ladder since then physically & creatively, and I just don't see him as a legit maine vent World Title holder at this point.
If he stays with TNA, just ride your brother's coat tails. If he goes back to WWE, be happy with whatever they give you.
Hardy will be just fine in TNA with his brother. Matt actually looked decent at the PPV seems he dropped a few pounds. As long as his brother is in TNA Matt's not going back to WWE and will possible re-ignited the Hardy's in a few tag matches in TNA against Beer Money!