I would like to see a fantasy action cartoon on a kid's cartoon channel like Cartoon Network with with likable characters, a strong linear melodramatic story with minimal random filler episodes and little to no cliches. Call me crazy for wanting a good cartoon to be broadcast-ed on and restricted by a children's network, but in my eyes, some of the really great cartoons are the ones that work under strict rules.
Take Regular Show as an example. If it were on Comedy Central and they were allowed to curse as much as they like, do you really think it would be as popular as it is now? Or do you think that it might just kind of get over-shadowed by cartoons like South Park? My point is, on a channel like Cartoon Network, due to the restrictions, it feels much more satisfying to get away with edgy and/or excellent content on a channel that is supposed to be for kids or is known for its lack of quality programming. I know that it is much more satisfying to see Regular Show get away with its many risky jokes and innuendo than on a channel that allows it, where you would expect it. You don't expect it, and it surprises you. That makes it all the better.
It would be great to have a show like that, one that was actually a legitimately good show despite being appropriate for your drooling 3-yr old cousin. It would be great to be able to look back on that show a decade later and think, "Huh, this show was genius. This is definitely going on my watch list." Should be similar in a sense to Pokemon (the games, not the show). Pokemon is genius in that there is no barrier to entry for younger ages. Your 5 yr old little brother could pick it up, play it, and beat it with relative ease, yet, there is so much more to it as well. It has a ton of strategy elements that put customization options of other RPGs to shame. There are an insane amount of ways to tweak your party to make it perfect that go past just types, but what moves your type can use, and the stats of that type to the point where even two of the exact same Pokemon can be drastically different. i.e., It doesn't need nostalgia, it can stand on its own two legs just fine and it offers entertaining accessibility to all ages.
That's the kind of cartoon that should be made. One that is appropriate for all ages, but offers something unique, interesting and/or engaging for each age group.