Writer Paul Dehn's original script was a lot darker apparently and the Caesar character continued with his tough stance against humanity, with Caesar being killed at the end. The studio wasn't happy and brought in new writers to make the script more family friendly, hence the rather limp finale for the series. Then there was the Saturday morning live action tv show and then the cartoon. I think a similar thing happened to Robocop. Hard hitting movies get softer and then it's kid's stuff.
However, despite having said all that, I still love all the original Apes run. Yes, even the cartoon.
