Great post, nhoj.
You’ve got several good points here, but this is something that isn’t brought up often and should not be overlooked:
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.
This shift from characters to caricatures infects many characters and aspects of ROTJ and is something every ROTJ fanedit should fight against.