Actually Mark Hamill opted to perform in stage productions rather than screen ones in an effort to not be type cast.
On a different note, simply because Gibson auditions for the role, I'm not entirely sure he would be cast as Skywalker, since I'm not entirely sure he could pull off the starry eyed farm boy. However he may have been able to do it, he has never been in a role that required a similar portrayal.
Who knows, this might have reversed the fortunes of Mark and Mel.
Bill Cameron said:He'll be younger than he was for Mad Max, he won't have had the schooling in did, and he'll be head over heels in a large Hollywood production. That means he won't or can't stand up for himself or any possible "darker" interpretation of the Luke character leaving Lucas' simple and simplistic "Mary Sue" to make it to screen with the same consequences.
I'm not up with the popular critique of George Lucas' hidebound vision. Sheesh, is there anyone on this board who thinks George is capable of thinking outside the box? (Okay, I'm not saying I believe the guy to be a great auteur. But the first trilogy is something.)
I think Mel not having the apprenticeship of NIDA and Australian productions could stunt him.
Though Heath Ledger didn't have much education IIRC.