I think it makes more sense for Myra to figure out the secret in Norman's past. She's suspicious and distrustful of him from the start. Because Jimmy doesn't speak in the first half of the movie, we don't know what he thinks about Norman. So we don't know why he wants to do research on him.
Also, I think it was a good decision in the movie not to have Jimmy talk until the town meeting. When he finally speaks up, his words alter the course of the film. In the original script, the first scene where he talks doesn't seem all that important. It's certainly not dramatic or game-changing.
Well, in the movie, Jimmy comes off as kinda dumb and frankly just a pawn of Myra for most of the storyline.
Showing Jimmy researching the facts of Norman's past would have justified all the talk about him having a bright academic future, etc etc. -- and smart enough to make decisions himself.
I agree it was smart to not have him talk until the town meeting. I would have given him a few more lines AFTER the town meeting, but not long speeches or anything.
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4) You ever seen Superman $#$# his pants? Case closed.
I see no evidence that Jimmy is dumb; he's just quiet and reserved. I also disagree that he's Myra's pawn. He's just confused and is trying to work out his issues. It takes him some time to realize he must make his own decisions about what's best for his future.
I think it works that his only other line is "I'll make it" near the end. Again his words change the course of the story. It's pretty impactful when all of a character's dialog is deeply meaningful.
I went to the site you linked, but didn't see the Jimmy/Dale subplot. Deleted scenes, script, trivia? Would you mind adding a short summary? Thanks, in advance.