I liked the portrayal of the old cartoon characters because, compared to the original comics, they WERE super lame. And after the pilot (which is pretty good, funny, well-written, etc., even if it is poorly animated--but what can you expect from 1980s American animation?), didn't they almost cut back entirely on using their weapons?
Anyway, the TMNT have consistently been in cartoon format for a long time, since 2003. :o Sadly, however, with Nickelodeon buying the property, they'll be making a CGI cartoon series based on the CG movie, I believe. That's not such a bad thing, I guess, but I'm afraid of Nick goofing everything all up.