Minor correction: the nitpicker in me is obliged to point out that Niven only wrote for the Animated Series, not TOS. Perhaps you meant Richard Matheson?
I used to joke about putting together an anthology titled THE ULTIMATE GREG, which would feature contributions by Greg Bear, Greg Benford, Greg Egan, Greg Costikyan, Gregory Frost, and John Gregory Betancourt. I'd edit it and write the jacket copy, of course!
...and Dumpo the Wonder Pigeon, in James T. Kirk Wears A Party Hat To The Federation Council! (sorry, just channeling Art Fern there)
Art Fern is a character that Johnny Carson used to play during sketches on The Tonight Show. Basically a used-car-salesman type who had a bad hairpiece and loud red jacket and was very hyper and almost manic. Every so often he'd stop what he was saying and go "Now back to our feature film...Woody Harrelson, Woody Allen, Woody Woodpecker, Woody Herman, Herman Munster, and Yutz the Dancing Buffalo, in Heidi Suffers an Estrogen Avalanche" or something like that.
But then the fans of the most recent movies will insist that the 2025 remake of TNG is a travesty . . .
TOS is the only true visionary Trek. The others including TNG are extrapolations of that singular unique vision and more an amalgemem of many different visions and takes on the same subject material. Only GR was able to harness and focus the efforts of the geniuses of the day into a collective gestalt. The others were like the bands that followed the Beatles and the child actors that followed Shirley Temple, etc. or the radio piece that follows Beethoven's ninth symphony. Certainly not an envious place to be but Brahms did it, etc. so it can be done, if you're Brahms.
I think TOS is the foundation of the franchise, and deserves respect for that, but it's not the only "True" Trek.