The Aluminum Falcon said:

What exactly is the 10-15% which will not be despecialized? Is it what I mentioned earlier:slightly different color timing, recomposites, different skies, different sabers?

Yeah, that's prety much it. But also changes like the DS detention block corridor extension, some new matepaintings, some of the CGI x-wings (only those that are not obviously CGI and look similar to the original) and stuff like that. Simply put I'm not aiming at a faithful reconstruction in terms of actual technical completeness but in terms of the viewing experience while keeping it as HQ as possible.