Some of what you say is true, from a storytelling point of view. However, it is also true that when you do pass a torch, the underlying meaning of the character does change somewhat (or quite a bit, when you consider that the title has been held by outright jerks). Doing that to such an icon permanently is... dicey, both in a business sense, and an artistic one.
I agree on all fronts.
But there is also something to be said for how bringing back characters devalues the drama of death.
And that it is possible to find equally idealistic & traditional people even in people born after the Vietnam war.
...or a clone.
...or from an alternative dimension.
The list of options before a true resurrection is pretty long, here.
Or that a different person with the same powers may let you tell stories you couldn't otherwise tell.
When Superman died, you got to see some of that in DC itself, but also in the many homage characters that sprang up (or got revived) afterwards in other comic companies' lines- Supreme, the Kryptonian Cyborg, Titan, Steel, Hyperion, etc.
A different take on Cap could be cool...very cool.
I make fun of the "boy scouts" too, I also agree that they are needed. For all of the ongoing dialogue in the last few years about how the darker characters make the hard choices to do what the other can't/won't do I think the "boy scouts" make the really tough decisions. They do the right thing always not because it's easy or works the best but because it's the right thing and no matter what there is always a way around doing the not-right thing.
Superman and Cap (some others too I'm sure) are the touchstones by which their universes measure themselves, like it or not. The problem I see is that too often they aren't written as the touchstones but overbearing, oh-so righteous, dorks that nobody can stand. It's the whole Paladin thing that OOTS showed pretty well.
Don't forget Capt. Marvel and...well, you're right, the list does go on a bit.
Though I must say, the occasions when the "boy scouts" do things we don't expect them to make for some interesting storytelling- like when Supes executed the 3 Kryptonian criminals in that alternate dimension.
Heck...if you really pore over a given characters' history, you may find that he's not as "Paladin-y" as you think. The early Superman stories featured a personality that was far more like early or Dark Knight Batman than the kryptonian we usually think of.
