That’s one of the things that I’d like Ady to consider changing, what many people have referred to as the “Flanderization” of C-3PO. While Threepio is certainly a worrywart, that personality trait has become a caricature in ROTJ. In ANH, Threepio successfully bluffed past Stormtroopers on the Death Star and was decisive in choosing when to leave hiding and try to board the Falcon. In ROTJ the caricature version of Threepio has been left out of the plan and (because of his ignorance) could easily work against it at any moment.
I would like to see any edits made that could instead have him included in the plan.
3PO is more than a worrywart. You’re ignoring Empire, where he says “I really don’t see how that is going to help. Surrender is a perfectly acceptable alternative in extreme circumstances. The Empire may be gracious and…”[Leia shuts him off]. He also dismissed R2’s mission in ANH in favor of hanging out with Luke and trusting Luke with any potentially classified information simply because “he’s our new master.” 3PO can not be trusted with sensitive information because he surrenders too easily when under pressure.
Meanwhile, R2 knows when to keep his mouth shut, so to speak.
With regard to the Camo Troopers—George said that he wanted the good guys to have earth colors while the bad guys were colorless. The troopers and Vader having stark white and black armor respectively was an intentional design choice.