TAS was done by Filmation, and they were like that with all their shows, right up to He-Man. For the time, it worked. It was cost-effective at the very least, and was slightly better than what Hanna-Barbera was putting out at the same time But once you got into the 1980's, and the stuff from Japan showed up (like Robotech, for example), that showed how dynamic aniamtion could be, people got tired of it real quick.
In an interesting aside, if you ever watch the new Teenage Mutant Ninja Turtles show on Nickelodeon, Leonardo's favorite show is a very Trek-like series called "Space Heroes," that has its animation style done exactly the same way as Filmation's TAS! Every time I see it, I can't help but smile, because they get it exactly right.