[Locke]

That is where I'm now struggling, when I think about it.

Because before being a Ranger, Carter was a hero so inherently that makes him the better Ranger.
But given the life Jack led, and the kind of world he lives in, before he was a Ranger he was a fighter and a practical thinker, who was world weary to be realistic about things. So he may not make for the better hero, maybe not even the better Ranger, but as an all out warrior I'd say he comes out on top.

Does a natural hero make him a winner? Or should the warrior with the heart of gold take it instead?

I'll stick with Jack still for now.