Yeah, none of those are adjectives you'd use to describe 'Captain Planet and the Planeteers' and we're not even talking about the ridiculous Belfast episode either.
A live-action 'Captain Planet and the Planeteers' movie has been in the works for several years now, although it's only since Leonardo DiCaprio's production banner Appian Way coming on board that it's begun to actually pick up some speed. That move was announced back in 2016, but a recent interview in THR with the movie's screenwriter - Glen Powell, who'll you know from 'Everybody Wants Some!!' and the upcoming 'Top Gun' sequel - has shone some light on the subject.
Powell states that 'Captain Planet' was his favourite cartoon growing up, but admits that "(sometimes) you have to think of these things logically. If you have a blue superhero with a green mullet, you can't do like an earnest take on that. You have to go at it from a fun (direction)." He goes on, explaining the producers previously "tried to make it into a superhero movie before, but they kind of did like an earnest take and ours is way more subversive and fun and like dark and irreverent."
If you're going for something dark, fun and irreverent with Captain Planet, it's already been done. Take a look at this sketch from 'Robot Chicken' with Ted Turner turning into Captain Planet.