Superhuman heroes are less interesting than heroes with limitations. Superman is, possibly, the most boring superhero that exists. Since he can do everything, all plot lines revolve around keeping him away from the action. Oh, no, Superman swallowed kryptonite. Oh, no, Superman is having a heart-to-heart with Lois Lane. Oh, no, Superman went to visit his parents on the North Pole. As soon as he comes back, you know everything will be okay—all he has to do is show up.
Limited heroes are far more interesting. Bruce Wayne/Batman takes the cake here, having zero superpowers, just a whole bunch of money. He must survive entirely on his wits and his cool gadgets. James Bond falls into the same category, although I admit that I've never cared much for James Bond. I very much like Jason Bourne (and doesn't it blow your mind to see boyish looking Matt Damon get all fierce and concentrated--woah!) who has even less gadgets than Bond.
This limitations business is why Angel and Spike of Buffy and Angel remained interesting. Angel could be incapacitated. Spike could be beaten up. Granted, the out-of-commission period was relatively short, but still . . . it heightened plot tension.
The all time best heroic moment in film is when Wesley, The Princess Bride, gets off the bed and raises his sword at Prince Humperdinck. It's marvelous because it's against the odds. It's also a bluff. Wesley isn't strong enough to fight the prince, but he is totally convincing. "It's possible, pig. I might be bluffing. It's conceivable you miserable vomitous mass, I'm only lying here because I lack the strength to stand. Then again, perhaps I have the strength to stand after all. Drop... your... sword. Have a seat." The prince takes a seat, and everyone cheers, and Wesley gets wobbly at the knees because, after all, he was dead less than ten hours earlier.
Factor Two: Knives Are Cooler Than Lasers
Actually, I think just about any weapon is cooler than a laser. There's a scene in Star Trek's Contact where Picard is being hunted by the Borg. He goes into the holodeck, set for a Chicago-style 1930s bar, turns off the safeties, picks up a machine gun and blasts the Borg full of bullets.
It's supposed to be a sort of anti-gun statement. See how angry Picard is! He's SO angry, he'll even use a *gasp* machine gun! See how angry it makes him!
The problem with the above is that watching Picard blast holes in the Borg is a whole lot more exciting than watching Picard zap them with his laser. And why killing someone with a laser instead of a bullet is suppose to be "nicer" is beyond me. They're still very dead. And personally, I think that if you're going to kill someone, you should at least have the guts to look them in the face, not vanish them in a puff of red light.
So machine guns are cooler than lasers. But swords are cooler than them all. Swords beat everything, even fists. Since the moment the first caveman discovered metal and then discovered you could whack people with it, humans have been fascinated by the stuff. It's poetry in motion, which has been said about something else, I just can't remember what. And it runs the gamete from elegant and suave to wolfish and brutal.
Factor Three: The Annette Curtis Klause Factor
Annette Curtis Klause wrote THE teen book about werewolves (Blood and Chocolate), and she uncovered the truth about the human fascination with animals. All the nature shows on PBS. All the Animal Kingdom programs. All the stuffed animals. All the fur coats. Darwin and Durrell and zoos all of it comes down to this: humans think animals are sexy. (See my post "Animals That Talk" for why I disagree.)
Consider Brian Jacques' Redwall series, the most boring series in the world in my opinion, but it's popular. Examine Animorphs and Harry Potter's Patronus spell. Humans are fascinated by animals. There's a very weird CSI episode about people who take the "we-wish-we-were-animals" stuff too far. And ironically enough, the guy dressed up as an animal gets shot by a farmer who thinks he is a coyote. Ironic because much of the fascination with animals is seriously one-sided. An animal will eat you or your food before making friends. And most pretty animals, like deer, are simply parasites with style.
People don't really want to be animals. Animals are stupid. Which is where werewolves and such come in. What fascinates us isn't stupidity, what fascinates us is smarts. We want to think the dumb ape with the sign language is communicating—well, I don't because I don't like apes, but I wouldn't mind communicating with a tiger. Except that all the tiger probably thinks is "Cold. Hot. Food. FOOD. FOOD. Sleep." So what I really want to know is what a smart tiger thinks. But there is no such thing.
Enter Disney and tigers with English accents. Enter C.J. Cherryh's series about an intelligent group of lion-like creatures (much better than Redwall by the way). Enter Wolvervine. Enter werewolves. (In this regard, I think Whedon made a mistake with Seth Green's werewolf look; it wasn't cool; it was just a weird-looking costume. But I don't suppose Whedon had the funds to borrow a wolf from some wild-life sanctuary.)
Factor Four: The Loki Factor
Loki was the Norse trickster. He's the guy, if you're into Norse legends, who caused Baldur to die. In Wagner's unending Ring Cycle, he is Loge. He is often ambiguous, an uncertain creature who may or may not be good but is often more perceptive than those around him. Heroes of this type are enormously attractive. Part of it is the Bad Boy Syndrome. But the young hot "God" of Joan of Arcadia has it so it's not just a Bad Boy thing. A great deal of it is wit (i.e. Rupert Everett). Part of it is the Dr. House/Sherlock Holmes thing: the hero may be eccentric but (s)he's smart and honest, more honest in fact than everyone else. And part of it is the ambiguity. Ambiguity sells maybe because it hits a nerve, maybe because with ambiguity, we can read our own desires into the character, maybe because ambiguous characters tend to be more unstable and therefore more interesting on a long-term basis. Largely, I think it is because we like seeing the underdog triumph. We love watching the cynical guy lose (just for a moment) his cynical edge; we love watching human decency emerge, if only for a moment. Spike is a good example; Spiderman; Snape; Q; Wolverine (definitely bad-boyish); Alan Rickman in just about everything; Gollum (I didn't care for him but he is fascinating to watch); Edmund (of the Narnia books--one of the most popular characters); Johnny Depp's character in Pirates (and just about everything else); the young girl (Jen Yu?) in Crouching Tiger; Modred (okay, I'm the only one who thinks he is a hero, but still . . .); Faith; 7 of 9 and Hamlet, just to throw in someone classical.
By the way, during this season of Star Wars mania, I should mention that I don't count Darth Vader's instant-presto redemption in Return of the Jedi. That's not an ambiguous character finding his heart (a la Han Solo). That's an evil character deciding not to kill his son and getting kudos for it. Yeah, right. Thanks evil person for not being as evil as usual today. It isn't the same thing as being ordinary and human and morally gray and then making a moral choice anyway.