I think it is obvious what Disney should do with the space. Turn it into a real Pizza Planet. Not like the one at HS, but like the one in the movie. Only bigger. They could even preserve some of the better attractions and just change them to a credits model. Update the outdated attractions and throw in a Pizza restaurant and several audio anamatronic zurgs and aliens and add a woody and buzz character experience and they would have people knocking down the door.
IMO, this is too big of a building taking up too much prime real estate at DS to have a band aid fix like that. It needs a complete overhaul of some sort. Just too much valuable space for it not to be something modern.