CatBus said:
The R2 in SW and ESB was a rude wise-ass with good intentions. R2 in ROTJ has a strong pollyanna vibe. For ROTJ R2, it seemed everything was always going to turn out just fine, you'll see. SW/ESB R2 had a lot more negative things to say.
Couldn't this be chalked up at least in part to Threepio's responses to him? While he's always bad-mouthing him in the first two films, I don't recall him doing so much of that in ROTJ.