The Galactic Senate

Now that's a fascinating theory I hadn't heard! I'd certainly get on board for that. And yes, he might be reasonably old by this point, but there's plenty of in-universe reasons why he could still be quite fit for his age. As for how Rebels ends... I don't think the ending can be too dark, which in ...

I thoroughly enjoyed the finale; but in particular, the scene between Obi Wan and Maul was very interesting. It's all tied in rather nicely so far.