Re: How to understand the SuperHero Genre
There is indeed a 'knack' to understanding the superhero genre. One of the best essays I've ever seen on it is in 'Shields of Justice', for Silver Age Sentinels, which discusses heroism from a comic book point of view.
Part of understanding the superhero genre (or, indeed, any form of fiction) is 'suspension of disbelief'. If you're the type of guy that can't watch a movie or read a book without thinking of a long list of what all the characters did wrong, why none of them should be alive, quoting from the 'evil overlord' list and generally running on as to how unrealistic things were... then there is little hope you'll even really be able to stand the supers genre because it depends on that suspension more than many other genres.
Really, you just have to be willing to let things go and trust in the genre to inform you of it's rules as it goes along. You might not be able to. I handed 'Shields' to one player that was having a hard time with supers. He came back and said he simply couldn't conceive of a character that would behave that way. Fair enough. Some people can't watch musicals because they can't get over the mental jump of how people just suddenly break out into song and lead parades through the park without getting arrested. Some people can't play aliens, or different genders, or whatever.
Some more modern-view comics deal with the genre conventions in terms of 'escalation', where the heroes and villains try to on some level maintain a sense of 'rules of engagement', just as classic espionage agents do. You nab the crook getting away from jail, you beat him up and drop him off back at the copshop, not kill him. Otherwise, they kill one of ours. They capture a hero, they don't reveal his secret ID on national TV, or we do the same to one of them. No-one wants to be 'that guy' that gets to be the example.
Or you can just look at it from a more practical form. Good villains get reused because they are good villains, and good well-drawn characters of any stripe are hard to find. Sure, you could have Batman easily kill off the Joker, but then your editor will say something like 'Simmons, that was amazing. You'll win the next two Eisners for that story. Truly one for the ages. I cried. Now, since the Joker is now dead, you'll need to come up with a villain that's just as cool as the Joker was, and have him on my desk Monday morning.' It becomes an exercise in meta-narrative at some point, but there it is.