CAPTAIN PLANET
These ideas where done years ago, trying to update this idea.
I'd redesign him to be similar to the Alex Ross Captain Mar-vell in Universe X. Where his body's shadows are like the universe (you can see stars and stuff) and make the planet on his chest a real spinning planet (in terms of looks, not necissarily a planet), his hair would be green and sort of flowing.
When his powers are off, or not in use, he returns to a regular looking guy in a red lab type body suit.
The Planeteers, ranks have grown to be a sort of small army, but the main Planeteers are still the ones from the show, only they are leaders and their powers have grown a little.
Maybe the guy (with the power of heart) has become the vessel or the body for Captain Planet.
Just some ideas.