Brilliant thread.
When I first heard about Matt Hardy, I started thinking about a Hardy Boys reunion in TNA as well. And where some see them as possibly being like the brothers of destruction, I see them being more like The Natural Disasters and I think there could a compelling storyline around it.
Jeff has put on weight and is in trouble with the law, Matt is fat and unstable.
These are two guys that are beloved by millions of fans. What I would do is a number of certain storylines, that focus on the downward spiral off the two.
One angle could be, Jeff and Matt reunite, and like any good actor looking to make art, they make sacrifices and by this, I mean Jeff and Matt continue to gain weight at a rapid pace. I think seeing this happen, will be gripping to the fans that have followed them. Watching them become victims of obesity.
Also, while getting fat, they could explore Jeff's legal troubles and have Jeff go to jail kayfabe. Like "Jeff Hardy was arrested this weekend." Just have the hardys be complete deadbeats, but in the ring they are just like Samoa Joe. And if Jeff doesn't really go to jail, just have him kayfabe be arrested once in a while, but only for short periods of time. Hell have both of them arrested for storylines sakes, for whatever reason. I could picture them being something like the blues brothers.
The fatter and more disoriented they become, the more legitamately threatening and violent they become. Jeff and Matt can run through most of the roster, b/c TNA has a lot of guys who are like 5'7 where as the Hardy's are like 6'1. Imagine them being a little taller then Samoa Joe, and fatter/more broad. Also they are brothers with great chemistry. I think they would be better then Tugboat an Earthquake were, just not as fat and better skilled in the ring.
A 300 lb'er doing a swanton off the ladder? Now that's cool.
Also, the storyline would be so raw and so disheartening for the young/hardy boys fans that it'd sure to be a hit. Watching them dissend from being the hearthrobs they once were, too middle aged, obese, mentally unstable criminals.
And other wrestlers could try and help them, but they get mad and attack them for it. And whenever you see them backstage they are eating and/or doing kayfabe drugs.
I think it could be great storyline.