Hard to say–while the new official 4K sources seem very good, they still ultimately need to blend with the 4K77/80/83 sources used for despecialization as well. Since IMO the 4Kxx releases still only resolve less than 720p of image detail, it would be hard to blend with the new 4K sources at greater than 1080p resolution without making the seams show between the two sources. Not that it’s not worth trying – there’s lots of tricks you can do with sharpening and fake grain that may help it blend.

As for the “edge over 4Kxx”, have you compared ROTJ:DE at 720p to 4K83 at 4K? While 4K83 is certainly amazing and looks great, ROTJ:DE already has the clear advantage in fine image detail (and IMO also in color, at least until DrDre is done with his 4K83 regrade). The advantage of negative/IP scans over projection print scans is already apparent right now at a lowly 720p, but could become moreso using the new 4KSE release – and that advantage could present a problem to despecialization efforts.

As for the Atmos track, the original films only ever had six audio channels at the most, and IMO preservations will only have six channels at the most too. Otherwise you’re just adding SE audio elements back in.