So, I'm still banking on a Kurt Angle WWE return.
The most consistent part of his WWE departure story has been that he wanted to work a reduced schedule. The old man had just gone to five hours of weekly TV and told Kurt they couldn't afford to have him work less than full-time, whereas TNA would.
Personally, I believe it was a combination of that PLUS Kurt's addiction and substance abuse problems that paved the road for his exodus. Vince was still in damage control-mode from the Benoit events. Kurt claims he told Vince that if he wasn't granted a lighter schedule then he would leave, and maybe this was McMahon's way of "pushing" Kurt out.
Well... Kurt's been clean and sober for some time, now. And, he's rested and in very good shape from the ample training time his TNA schedule has allowed.
With the increasing number of past stars now working a VERY part-time schedule ala Brock, Rock, Taker, etc., I can easily see Kurt try negotiating a similar deal. This would get him back in the company, give him some fresh talent, angles, and material to work with, and offer larger merchandising opportunities with WWE's larger fan base. I'm thinking a Kurt Angle anthology DVD set - they've certainly got enough material for it!
Also, Kurt was SO over for SO long in the Fed, that I'm all but certain that his return would be HUGE!!! As he nears the end of his in-ring career, this would be an incredible high note to go out on.