I think Swamp Thing is one of the best properties DC has that there isn't in some stage of active movie development. On clips from the old movies/TV shows or whatever on Youtube, you'll have people who don't even know he's a comic character saying Swamp Thing is overdue another shot at the big screen.
I think between the films, the TV show, the cartoon and the toys, Swamp Thing has a cultural awareness amongst people of a certain age that surpasses many of his more "iconic" superhero contemporaries in the DCU. And by taking the work of Alan Moore as a cue, there's material to make a really deep, powerful movie that could surprise even fans of the original series, much like what happened with the new Batman films.
I actually quite enjoyed Wes Craven's original film. It had great location shooting, and some atmospheric directing, and Ray Wise made a good Alec Holland. But once we actually got to see Swamp Thing, it fell apart. It wasn't just a guy in a rubber suit, it was a guy in a really bad rubber suit. If ever there was a character who could really benefit from the advances of CGI/motion capture technology, it's Swamp Thing.