So what you're saying is there will be an ROTJ Chewie within 2 years? I dunno man. It makes sense for a lot of other figures, but Chewie is basically Chewie the whole time. How could they re-release a Chewie, with what else? A bag to carry C3? Some wrist cuffs? I don't see them revisiting this any time sooner than the time it took for them to eventually revisit Emp Palps. It's the same character no matter the movie. HT has a lot more to chew off before they try to revisit this guy.
Like I said, you haven't been around long enough then. HT will milk Chewie for what they can -- with exactly what you said: a simple color improvement, fluffy eyebrows, some binders, a barge staff... and of course, a bagged Threepio.
Oh, they will make another. Besides the inevitable "Force Awakens" Chewbacca.