Sam Carter could probably take over the genre even if we did let other Sams in. I'd offer up Sam Tyler, but, uh, for some reason, in my brain, his time is less-than-evenly split between kicking ass and being confounded by Jack Harkness. (I've noticed that Jacks and Sams seem to go together, oddly. They always have such fascinating interactions and relationships. And then eventually you have to come up with group names for them; I have concluded that the proper terms for groups is "a confusion of Jacks" and "a repression of Sams." It seems to hold.)