I'd guess (and hope) we're likely to see a slightly-over-polished version and not just a straight restoration. There is no particularly compelling reason to restore the matte boxes around TIE fighters or to leave out Ben's blade from the couple shots they were trying to use a practical effect for it in the Death Star duel. I think the key is to go with original intent. No adding anything, just making the existing effects look as good as could potentially have been accomplished at the time using the methods they used, even if that means recreating and recomposing them digitally for an overall more compelling result.It is going to happen, and Ultra HD is the reason why. Reliance Media Works (formerly Lowry Digital) completed a 4k 16 bit restoration of Episodes IV-VI last year.
It was George's own over-reliance on CGI that did him in; the SE effects were never meant to be seen at 4k resolution. To remaster the Special Editions in 4k, all the CGI would have to be redone from scratch. (Not an impossible task, but quite pricey.) Ditto with TPM. AOTC and ROTS are disqualified from 4k, as the live-action elements were shot using first-generation digital cameras that went up to 1080p and no higher. The pre-SE film prints, however, can be easily scanned at 4k - models, animation, stopmotion and all - and for relatively cheap.
Lucas ain't in charge anymore. Disney knows how much the fans want this. Fox will have no problem striking a profit-sharing deal. It's gonna happen. It's a matter of when, not if.
People want to see the movies they grew up with, but matte boxes that weren't visible on their well-worn VHS tapes doesn't have a place in that memory and will be distracting to viewers both old and new.