Heroes (and villains) can do specific things. Flash moves fast. Batman is smart and fights well. Superman can fly, is really tough and really strong. Green Arrow shoots arrows well. Exactly how fast, how smart, how strong, how well etc., are details that can vary as the plot requires. But the essence of what the character can do is concrete and it's fairly easy to imagine plots that challenge them or where failure is possible, allowing for dramatic tension.
A lot of Silver Age writers took advantage of "concrete powers" to create three-act plots:
- Hero encounters villain and loses (the villain accomplishes his goal and escapes).
- Hero encounters villain and there is a stalemate (the villain's goal is thwarted but he still escapes).
- Hero encounters villain and wins (the villain is both thwarted and captured).
A classic example (don't laugh) is the original (um ... and only) Aquaman versus the AWESOME HUMAN FLYING FISH story.
- On the first encounter, Aquaman is taken by surprise by the HFF's aquatic and flying powers, and the villains gets away with the loot.
- The next time, Aquaman has wised up and has a strategy that takes those powers into account; he stops the theft but the Fish gets away.
- Then, Aquaman, always a thinking man's hero, sets a trap for the Fish, which succeeds.
A hero with concrete abilities encounters a situation or opponent that challenges those abilities and through increasingly strategic use of those powers -- or simply cleverness -- triumphs. The hero doesn't win all the time; he simply wins in the end. It's remarkable to me how easily many people confuse the two.
Storytelling starts to stumble when hypostatization -- treating an abstract power as if it were a concrete one -- begins to take hold of the character. Flash as "really fast guy" even "the fastest man alive" works. But when he becomes (as the modern Flash has) the Wielder of the Speed Force, controlling the very concept of kinetic power (as he does not with his "kinetic distribution power") his powers are hypostatized, rendering him nearly unwritable.
This happened to Superman in the Silver Age. Superman could not be harmed. PERIOD. Talk about treating an abstract idea as if it were concrete! Magic & kryptonite, that was it; otherwise, forget it. The result? Every other story has to have either kryptonite or magic in it. Yawn. Throw in the ability to travel through time at will and a couple pounds of Amnesium, and rooting for Superman becomes pretty much redundant. No wonder Supes degenerated into sitcom and soap opera (*choke*!).
Batman has been called "the world's greatest detective" but that really doesn't mean much unless he's engaged in a one or one "detecting battle" with an enemy. Batman has pretty much escaped hypostatization (although Morrison teetered close to it with his Perfect Batman With A Plan schtick). You can still believably beat the crap out of Batman. Nevertheless, the effects of Morrisonesque hypostatization of Batman is noticeable in the hordes of young fans who simply denied that it was possible for Hal Jordan to hit Batman, as if Batman's unbeatablility were a magic power.
Marvel characters are usually overcome by hypostatization when they fall for their own press.
- Green Arrow is a darned good shot but Bullseye is The Man Who Never Misses (tm).
- Green Lantern's willpower is stronger than fear, but Daredevil is The Man Without Fear (tm).
- Wolverine is The Best At What He Does (which is killing, as far as I can tell; nice power, bub).
- And, of course, "nothing can stop the Juggernaut"!
As a character's powers grow more hypostatized, there are more and more obstacles to writing the character. An occasional hypostatic figure can be fun and colorful, such the Quiz (from Morrison's Brotherhood of Dada), who had Every Power You Hadn't Yet Thought Of. But when your mainstream pillar characters start to fall victim to the Hypostatic Syndrome, then a reboot becomes inevitable. The "de-hypostatization" of the Flash and Superman was one of things the post-Crisis world was supposed to accomplish. It did.
But then the editors let the writers forget the real reason the Crisis was necessary: not because the world had become too complex but because its characters had grown too powerful to write. And now the Spectre, who has essentially been deified, is cruising for a bruising, too, necessitating Day of Vengeance.
Contrary to popular belief, readers don't lose interest in a character once they realize he's not going to lose. They lose interest in a character when they realize he cannot lose and still remain who he is... which is different thing entirely.