Jeff Hardy has certainly burned a lot of bridges during his career, but people are still interested in watching him wrestle. He has been with TNA for a few years now, but speculation is starting to grow that the WWE is looking at bringing him back once his contract expires. Adding him to their alumni page is only going to increase the chatter.
If the company does bring Hardy back, it will probably be on a short leash. They have been burned by him way too many times and you never know the mindset that he is going to have coming in. He might give you one solid year before things start getting weird for him. Considering that he is extremely popular still, it might just be a move worth making.
Hardy would not be expected to carry the company or even carry a belt. I can see the company using him as a way to get younger talent over. Hardy will always be a face wrestler, no matter which way you slice it. It is way too difficult to get him over as a heel. There are a plenty of young heels in the business, so a guy like Hardy could give them a decent rub as they try to improve their careers.
Nothing is set in stone and all of this is just speculation, but the recent moves by the WWE seem to indicate they are putting feelers out there. You know a lot of fans are going to be waiting to see if he will return to the company soon.