Hey I *love* George lucas and EVERY movie he has ever made, except American Graffiti, but that's besides the point.
Jennifer Connelly gave a pretty good performance in Labyrinth, um, I can't think of any good acting in Willow besides the Brownies, The Indiana Jones movies DID NOT suffer the same horrible acting and cheesy dialog as the Star Wars Prequels (of course the had Spielberg on board who is thousands times better than Lucas IMO) and let's see, Radioland Murders, well they had better actors all the way around and it didn't suck, (Even if the dialog was cheesy *that* was a comedy and you can forgive cheesy dialog and bad acting in a comedy)
The idea that the actors were bad *because* they were in a Lucas film, is ridiculous and tells me you haven't seen *ANY* other movies made by Lucas except Star Wars (and if you tell me Howard the Duck was any good were done talking)
Now Lucas wasn't always Director on all of those movies, so maybe that might have had something to do with it, but Star Wars, the original, was damn good and look what he had to work with.