Distribution rights are just that: the right to distribute. They don't "own" the films, they have no say on what to release and in what quality. As it stands, Fox is the only company who can ship the product on shelves, but they don't get a say in WHAT is released.

If we are to get a Star Wars blu ray in the next couple of years, Disney and Fox will have to make a deal. They'd have to figure out who gets how much a percent of each sale. It's not exactly rocket science. The lawyers will be busy but there's a lot of money to be made, and I'm sure they can come to some agreement.