I think a show set on a different kind of ship, like a hospital ship, would allow for a certain amount of serialization, but also allow great standalone episodes. It would also allow for different kinds of stories than we've had in the past.
People seem to overstate the serialization of DS9. Even with all of its long arcs, about half of its episodes are standalone - even more earlier in the series. I do agree with the OP that DS9 has aged the best of the big three, but I might be biased because I've loved (nearly) every minute of it since the beginning.