I agree that soon after the ST, the "numbered" saga films should end. Cameos and guest appearances are fine, but I feel that once the torch is passed to the new generation, the story we began with the original Star Wars has been told. But the good thing about having nine movies is that there are going to be a ton of stories to tell between and around them.

If we look at Rogue One, for instance, they're drawing from the opening crawl of Star Wars. Even just going through the crawls of the OT, there are at least two other big stories to be told there: the founding of Echo Base between SW and ESB and the search for Han Solo between ESB and ROTJ.

Beyond all of that, there are references to dozens of possible movies within the films themselves: the abandoned Rebel base on Dantooine, the bounty hunter on Ord Mantell, the Battle of Tanaab. I'm sure the Rogue One model for taking these references to build films from will be their main source until they run out of them.

But that's just stuff that's related to the films, there are thousands of potential stories in this huge galaxy. Wookiees, Mandalorians, Stormtroopers, Jedi, Sith, popular Legacy characters... the Cantina is full of potential stories. It'll be like the "Tails From..." books, I'm sure. It's all very exciting.