See, people don't give kids enough credit. There's way too much of this "Poké-trash" on the air now, we need stuff written in a way to be okay for kids, but intelligent enough for the adult audience.
When I was 6, Transformers were all I could think about. Transformers, Go-Bots, Thundercats, and M.A.S.K., but mostly Transformers. A few years later, when I was 10 or so, TMNT came along to finally fill the void left when they took Transformers off the air. I loved it. But by that time, I was already reading Stephen King, John Saul, John Grisham, and Tom Clancy novels. I read my first 1000+ page book when I was 9. Now, while you might think that makes me some sort of prodigy, the fact is I was a C student at the time. I just didn't allow anything to "dumb down" to me. I was capable of understanding plot and story at an adult level, and sought out plot and story with some smarts. Even as dumbed down as I now know the original cartoon to be, it still had a set of rules, a science laid down that it had to follow, plus an interesting character dynamic. Then when the first movie came out, I was blown away. Here was something that entertained my preteen mind without speaking down to me.
When Peter Laird first announced that a new series was in the works, I was worried. My mind flashed back to the short lived live action series and how incredibly lame it was (and I really didn't have a problem with a girl turtle, just with how unprobable her origin was). When the new series finaly debuted, all my fears were put to rest. It was like reading the first issue of "Ultimate Spider-Man" all over again. The story wasn't rushed, time was taken to fully develop the characters, everything I expect from an hour long drama at 10 PM in a half hour "kids" show at 11 AM (then 9 AM and now whatever time slot they're moving it to this week) Sundays (or Saturday, if you have a decent Fox network, around here, our WB network shows Fox's Saturday cartoons on Sunday morning, and their weekday cartoons in the early AM while the sucky Fox channel shows more Jerry Springer and Judge Brown reruns).
But I digress... Back on topic... Kids are smarter than we give them credit for. The show has not done anything too "dark" or complicated to be understood by an 8 year old. Hell, I was praticaly cheering when Leo cut off Shredder's head. Granted, Shredder didn't die, but that wasn't the point. It showed a mortal consequence that haunted Leo, and had continued repercussions when Shredder's adopted daughter came into the picture seeking to avenge her master. And now we're seeing more adult consequences as the daughter comes to learn of the Shredder's true nature.
Think of it this way, Sesame Street's African version introduced a Muppet infected with HIV, to help educate the young about the disease, its dangers, and how it spreads. They are refusing to speak down to their audience, and are helping prepare them for the reality they face. Not since the death of Optimus Prime have we seen "kids" programming here in the US attempt to do that. The new TMNT is first show over here to do that on a consistant basis. For that, I must applaud them.
(One last note: Batman Beyond: Return of the Joker did play on a more mature note, but failed when they edited it before release. As much as I'll grant points to WB for later releasing the "directors cut" DVD, the edits should not have happened in the first place.)