Y'know, both of Legend's joke threads raise an interesting point. Star Trek has suffered from never doing a new show with an entirely different premise.
No, Star Trek has suffered from not doing entertaining episodes. Star Trek is about people in the future, on spaceships. It's not anything else.
Then what's the difference between Star Trek and B5 and Firefly and Futurama? Is there really no difference at all between those things? Is Star Trek really just a hollow nothing, defined by shallow window dressing elements like "spaceships"?
That's Star Trek's premise (well, to be more precise: an optimistic vision of humanity's future is the premise, and prosperity & unity are important factors that bolster the premise).
I would submit to you that this premise manifested itself much differently in TOS than it did the later series.
In TOS we saw the characters striving to achieve those optimistic goals.
...
Thankfully, DSN went a long way to pulling things back to the original TOS world-view that had captured my imagination in the first place.
Exactly. TOS and DS9 are the series that got the premise right. But the other series at least were created by people who understood there's more to Star Trek than "spaceships."
