Cartoon Network has a lot of potential squandered by the idiots running it.
The Hub, on the other hand, seems pretty receptive to what their fanbase wants and does a really nice job of picking up old shows that fit right in with their existing lineup. Sure, it's a network that exists to promote toylines, but it also understands how to actually promote and schedule its shows in such a way that it actually benefits those brands. Like taboo said, Nickelodeon doesn't really seem to have any idea as to market Korra and Cartoon Network is, again, ran by idiots. It says a lot when The Hub is running a Batman The Animated Series marathon this Friday when The Dark Knight Rises is released into theaters and Cartoon Network apparently isn't doing anything with any of the numerous Batman shows that they still have the rights to.