Everyone dunks on TAS but it was amazing for it's time.
New cartoons for 1973 included garbage like Inch High Private eye, Goober and the Ghost Chasers , Jeannie, and Speed Buggy (I had a Speed Buggy lunchbox). Besides TAS, the only other good show released in 73 was Super Friends.
But Super friends was childish in comparison to TAS.
Back when the only Star Trek property was the Original Series, this could have really pulled Star Trek's visual style in a completely different direction. Who knows how much of this Phase II would have adapted into live action.
The Motion Picture completely re-centered Star Trek's look and feel and set the tone for the rest of the franchise for decades.