Supertights replaces Spaceballs because Star Wars is less of a phenomenon, and superhero movies are wildly popular in TTL. I'd like to think that Bill Pullman still plays the lead. Maybe Brooks can play the parody-analogue of Perry White?
Best of all, you can keep the line, "This is why evil will always triumph, because good is dumb." Heck, Rick Moranis probably still auditions for the role of Less Loser.
Great update, ColeMercury.