3.0 will be 1080p and contain zero GOUT footage. The biggest difference will be from SW 2.7 to 3.0. Though I removed most of the shots that were 100% GOUT (some quick shots of ships in the final Death Star battle wouldn’t have looked too much different substituting SSE for GOUT), there are plenty of shots that use GOUT elements mixed with blu-ray elements. AFAIK, those will all be updated. Furthermore, it is likely that a better 35mm scan than the TN1 scan will be used that will make everything even better.

The differences for ESB and Jedi going from 2.5 to 3.0, as I understand it, will be further adjusted blu-ray color correction, and a bit more cleanup/matching of the 35mm sources. More modest changes than SW, aside from the 1080p factor. Harmy is doing his 2.5 35mm work at 1080p, so it should be much less work to upgrade V and VI in theory. The blu-ray work for those two is still only at 720p, though.