I'd argue even Superman hasn't had a definitive movie treatment. Or anyway, nothing made up til now has fully captured the character the way I imagine him. The only thing "definitive" (as in, no need to ever attempt it again) about
Superman: The Movie is John William's theme. And
Superman Returns, though I really like it, can't be definitive for the simple reason that it is so darn derivative. (If it were a definition, it would read simply, "see
Superman: The Movie").
The closest thing to a definitive treatment of Superman on screen remains the Fleischer cartoons.
I agree about Tarzan. The funny thing is I always get the impression people shy away from the literate nobleman approach because they think it would strain credulity. Raised by apes? No problem. Able to kill lions with his bare hands? Done. Lives in the wild but never grows a beard? Fine. But able to read and write, hold a conversation and understand science and politics? Come on, that's just silly.
Also, while I liked some things about Russell Mulcahy's
Shadow film, I would never term it definitive. I'm looking forward to seeing what Sam Raimi does with the concept. (Obviously the less said about George Pal's
Doc Savage the better, though I for one am grateful the Schwartzenegger version never got off the ground).
I'm all for trying over again...every character is open to reinterpretation. It's only been a couple years since
the Hulk but since it went over like a lead balloon they're already working on a do-over in a new style. That's cool with me. But then, I'm a guy who likes all 6 James Bonds (to varying degrees), so I'm big on variety.
Having said that, I think "definitive" can be a very subjective thing. No matter how many times they do Batman, Adam West will always be the genuine article for me. And "Flash Gordon" is by now defined almost as much by Buster Crabbe's hyperactivity and goofy FX as he is by Alex Raymond's art and plots. But first isn't always best; I consider Jeremy Brett as close to a "definitive" Holmes as we'll ever get. I'm willing to see other actors take a stab, but if they stopped doing Holmes films today, I'd be content knowing the Grenada series got it right.
I will say this. Considering how many pulp and comic characters there are, it gets a bit boring seeing the umpteen-millionth version of Superman and Batman instead. But I dont' think that was your point.