For me, the last few Next Gen seasons epitomize that "safe", blander consistency. Their priority seemed to be not to make embarrassing mistakes rather than aggressively pushing the show into challenging, unknown areas.
There were exceptions: Forces of Nature, Dark Page, Lower Decks,
just to name a few. But overall, yeah, that was personally my impression of TNG's last -say- two seasons, as well.
As to the OP's question. I'm going to concur, from the standpoint of writing (to pick an essential standpoint) that the original The Twilight Zone
wins. I must fully disclose, however, that while I've seen most original TZ episodes, I haven't seen them all. What I have seen, though, leads me inescapably to conclude that there is a huge variety of solid, exceptional, moving, and memorable episodes.
TOS is very definitely second.
has a list of comedy science fiction shows. Personally, I'd add Get Smart
and I Dream of Jeannie
to that list.
Interesting also is that Saturday morning/children's shows seem to have been excluded from discussion. To name a few, off the top of my head:
Star Trek—The Animated Series
Land of the Lost
Far Out Space Nuts
The Lost Saucer
Jason of Star Command
The New Adventures of Flash Gordon
He-Man and the Masters of the Universe