I lean away from the mains only because their stories would all 3 be so separate... some one-off shorter arcs would be awesome though, like I mentioned above, that would feature things like Han saving Chewbacca, winning the Falcon, doing the Kessel Run...
What I'd like is to see this follow the war, and follow people involved in the war... It's sad but The Clone Wars didn't do that steadily. It deviated, and wound up losing the very thing it was based on at the start. It began so promisingly as well, with things like the Echo/Fives/Shineys at the outpost... or the Separatist "Bismark" arc... They had really insanely good stuff early, then up and gone like a fart in the wind. They then needed to focus on shoe-horning Darth Maul back to life and into the show, or things that were too kiddie... or conversely, "political intrigue" or other plots too complex. I honestly think Lucas came in and really **** all over the project.
This era, I really hope he is far from it. He should be at this point, but he's still there looking to get involved I'm afraid. I'm ready for new Star Wars from new people.