All arguments aside, here's how Filmation approached TAS, as related on pages 96 & 98 of the fascinating book, Lou Scheimer: Creating the Filmation Generation:
Lou Scheimer (2012): "The network had absolutely zero creative control for Star Trek; they had to accept the show or not accept the show, and I believe that was the first and last time that happened in the history of Saturday morning animation."
Norm Prescott (1973): "This is the first attempt to do an adult show in animation. Never before has an adult audience been challenged to watch a Saturday morning show. We feel it is a bold experiment."
Lou Scheimer (2012): "Wherever she (Dorothy Fontana) went, she begged the fans not to hate the show because it was animated, or it might kill the chances of Star Trek ever becoming another TV show or a movie. And once the fans heard how faithful we were being and how much care we were taking to respect the intent of the original series, they soon came over to our side. Word began buzzing to the 3,000 or so Star Trek fan clubs that Star Trek was coming back!"
As noted yesterday, TAS was attempting to pick up where TOS left off, only it had to fit the natural 52 minutes into 22 (better known as the 30 minute format). Limitations existed to a degree, but it was a worthy "next chapter" of TOS, and at the time, the only other truly adult U.S. cartoons to air before it were Jonny Quest
(1964) and Wait Till Your Father Gets Home
(1972). Pretty much a ghost town where adult concepts were concerned.
TAS stood out like a flower in the desert, and felt nothing like any animated production before or since; it cannot be compared to another series, has no "clone" or "sister" series, and that is not simply due to the content. It was just special, and at the time of its NBC run, I was quite disappointed to learn the series would not have more than its 2 short seasons.