Honestly the Coruscant background doesn’t bother me that much. I think it looks a lot better than the backgrounds in some of the deleted scenes, especially the Mace and Obi-Wan deleted scene, which hasn’t stopped it from being used in all the most popular fan edits: https://www.youtube.com/watch?v=IeK8HoReVo0

To me, the biggest issue with getting the footage to mesh well is actually the lighting. Due to the use of the volume it’s very natural, with daylight illuminating the background and the foreground mostly in relative shadow. This is in contrast to Attack of the Clones, in which scene like this would have been shot in front of a green screen. The actors and the foreground elements would have had to be evenly and brightly lit in order to clearly key out the background. George Lucas also tends to go for more traditional lighting and staging techniques in general.