Why not indeed? After all, GL did step aside to a large extent on Empire Strikes Back. Irvin Kershner directed it, and brought it in millions overbudget. He had a pretty hard relationship with George Lucas throughout the making of it...but without Kersh, there's no way ESB would've been as huge a success as it was. It's always the director, not the actors, that makes a movie good or bad--otherwise every Harrison Ford movie would've been a smash every time. Steven Spielberg directing RoTS would've been a treat. But that's off point. Other stuff I'd like to see in RoTS? Something to tie in Luke's offhand remark during "Empire" when he and Artoo first arrive on Dagobah: "Still...something familiar about this place." A reference, perhaps, to a hidden meeting with the twins on Naboo? Or even better, Yoda "meets" Luke.