As far as focusing on Starfleet for a future TV series, it would have to focus on a Starfleet crew to some degree. It would be like 007 series without Bond if you didn't have Starfleet in there, it wouldn't be Star Trek. As far as locale / backdrop, that has proven to be somewhat flexible.
Going by Star Trek History, we have Starships and Starbases as usuable backdrops.
Unless you want to turn Star Trek into some "Law & Order" style franchise with massive spin-offs that focus on different aspects of the "Star Trek" Universe, it's going to be hard to break tradition. Not that it can't be done, but you're going to have to start the initial revival on a Starfleet crew on a somewhat familiar backdrop such as the Starship / Starbase.
Then with different spin-off's you can do different things.