I predict an ROTJ Jabba's Palace big box next, with an Endor small box following that. I DO expect a Rebels wave and possibly even a Rogue-One inspired wave, but I think they will come out after the ROTJ box. Here's why.
Doing a full ROTJ set will complete the original trilogy in terms of movies. Naturally, at some point they are going to want to start working on a new cycle of the sequel trilogy movies - but the problem is, they can't start working on a Force Awakens box yet if they want to follow the same release schedule and format they've been doing and keep it on the same timeline. They'll simply run out of movie.
So ROTJ will put them well into 2017 before it's done. Then they can do 2 more waves of PRE_Battle of Yavin stuff, IE a Rebels Big Box, and a Rogue One small box, or vice versa. That should take them well into 2018. Once that has been delivered they can begin released sequel film content. Episode 8 will have been out already and now you've got 2 movies with which to make content. By the time we get 2 boxes for Epi 7 and then 2 boxes for ep 8, episode 9 will have come out and we can complete the sequel trilogy cycle with 2 boxes from that film as well.
And if we want to go even longer-term, the OTHER anthology films can either be spent on standalone expansions like Obi Wan and the Inquisitor, or they can wait until after episode 9 and be included in an anthology set.