They are ultimately NOT separate if they are still part of the bigger story. THAT is the problem, that thinking they are separate because they are "one offs" this is what confuses people. They started using those words to ward off rumours of them ever doing side trilogy's with these side stories because fans started getting worried. Thats why they always come out saying NO this is a one off story, there will be no sequel to it. Now do I ultimately believe that? Nope not for a second, especially if theres room for it and if the movie is widely successful. That being said a movie being focused on ONE character told in the the lineage of ONE story doesn't make it a separate movie. A separate movie would be a new made up character that we've never seen before that is far away from the Galactic War and no ties to any of the characters in the main trilogy.

I think the one place of the ONE story they are creating where they could really experiment and go the Game of Thrones type route while changing the feeling and the look is if they do The Old Republic. That wouldnt have to be necessarily funny, it could have a one-two jokes the way GOT has here and there. I think this would be the perfect starting point to experiment with tone etc. but even this still has to the things we love about Star Wars because its is also part of the ONE story.