2023 makes sense if that is Hasbro's plan. I have a feeling this line may run it's course in short order, especially if it gets hit with the "no plastic packaging" thing. There is no way you can continue the line without the figure bubble.
I don't mind them skipping the original Kenobi for the new one. I don't think the line would run long enough to cover every figure that was released. I'm fine if they release only one wave from each of the OT movies.
Here are my guesses for ROTJ wave of six: Jedi Luke, Either Boushh or Endor Leia, Endor Han, Biker Scout, an Ewok (probably Wicket), Bib Fortuna. I could also see either Skiff Lando or General Lando. I would think the first three are pretty solid based on the other waves. As for the "game" pack-in figure, my first guess would be a removable helmet Vader.
Anyone see a picture of what I would say is a rumored SDCC exclusive at this point? I saw someone post a Jabba's throne from the Book of Boba Fett. Not sure if it was real or not.