A good friend, and fellow Indy fan, brought this to my attention:
I'm sure most of us have seen the "Making of Indiana Jones" DVD featurettes so many times, that we can quote it fowards and backwards. You'll recall that in TLC Lucas was opposed to Indy Jr and Indy Sr having a relationship with the same girl. It would appear that Lucas had given in, in order to satisfy Spielberg, Connery, and Ford. Also note that there is absolutely no profanity in Star Wars.
Without knowing George Lucas personally, he has seemed to reveal certain aspects of his character through interviews, documentaries, etc... He prefers to not cross certain moral boundaries with his stories. Connery stated "...sleeping with the same woman was a bit of anathema for George..."
My point is this: I agree with Pale Horse regarding this concept of George not being happy with the Indy character from Darabont. I strongly believe that the reasons that Lucas rejected Darabont's draft was because he took Indy's character in a direction that was too "immoral" for George. And THIS time, George didn't want to make the "same mistake again" (I don't think it had anything to do with the action of the story. I bet Lucas was pleased with the action parts of Darabont's script!) It had crossed a hard line for George! And if it was one or two little parts, I don't see Lucas throwing a huge fit; he could just rework little bits. It must've been some HUGE thread of the story hinged around something "immoral" for George to fire Darabont and start over!