I think it's just not possible because the landscape in television has changed too much since the '70s. It seems the main motivation for the original animated series is that fans were hungry for new Star Trek in some form, and there wasn't a budget available for a new live action series, so the cartoon was made as a valentine to fans. It's quite the opposite of the situation now where after two bad movies and two series that weren't very successful overall, people are burned out on Star Trek. If the last three shows had never happened and people were missing TNG so badly because there hadn't been any Star Trek on TV since 1994, things would be different, but the reality is this is probably the least promising time for Star Trek on TV in the whole history of the franchise. With that said, to just forget about the reality of the situation and talk hypothetically, I too would love a TNG-based animated series. Patrick Stewart has already proven on "American Dad", "The Simpsons", and many other voiceover performances how beautifully his acting and awesome voice can translate into animation and has become quite adept at voice acting. I'm sure he'd be great as an animated Picard and would lead the other actors nicely. The animation would also probably be much slicker and smoother than the primitive filmation stuff, and just as it was with that show, it would be lovely to witness the adorable spectacle of those familar Star Trek voices coming out of drawings. I can especially imagine how enjoyable it would be to see a cartoon Data, resurrected and once again in season 1 shape, without Brent Spiner even having to go on a diet.