Hey, watch the West. Batman was as much a conscious self-parody as it was a straight action show. Planet doesn't have that excuse.
It had lofty goals, and occasionally got a good message across - but, as we've heard, even the messages themselves didn't have a great track record, and the execution failed to varying degrees of miserableness on nearly every angle.
Desdiablo's got a good idea. Give the issues behind pollution their due, or if they're too complicated for a kid's show (don't be too quick to count this out; some are more complicated than I'd care to get into myself), at least acknowledge that there are issues driving them. It's been a long time, but it would help to linger a little less on the terrible effects of pollution on the environment, and a little longer on the corrupt businessmen and their kin. Deal with how much time and money they're saving with their practices. (Heck, flesh them out in general. Complex characterizations for everyone!)
I'll spot the show some demonized antagonists - frankly, again, it's a kids' cartoon we're talking about, not that "adult" live-action shows are above that. The show should still deal, unflinchingly as possible, with why people who pollute, from casual littering to grand-scale waste dumping, do what they do. We don't want the kids watching the show, hearing the message, then falling into the same traps. Drive it home as solidly and realistically (as much as a show with a premise like this can get) as possible.
Granted, hindsight is 20/20, but it's still kind of painful to see a show with so much potential...