Every special effect wasn't recomposited. The whole speeder bike chase for example wasn't. Outside of running the major battles/ setpieces twice, there's not an unsurmountable number of alternate shots, and modern branching can probably handle it, especially Jedi. That one was really half-assed in 97. (The Close Encounters blu-ray is branching a whole lot of subtle differences among the 3 different versions it has. On the other hand, the people who did the Superman restoration in 2000 didn't even consider recompositing to be a "change").