I agree with your choice of iconic characters as far as it goes. I would express their meaning a bit differently, in terms of what they mean to the reader. Once I do that I can justify adding a couple more and some variations on the theme.
Superman is the ultra-noble vision we have of ourselves. Enormous abilities, enormous powers, but all under the control of homespun values so that we can resist all temptation and dedicate ourselves to good.
Batman is “revenge is a dish best eaten cold” turned sideways to show that the best revenge honors the family but extends its meaning outside the nuclear structure. It’s revenge conquered.
Spider-Man is the insecurity inside us needing to be repeatedly overcome with our newfound abilities as we grow older; the lesson that not only does great power bring great responsibility but that responsibility never ends - it just asks more and more from you.
Wonder Women is the strength we get from our heritage made manifest. She is the history and family and belief that guide us and give us determination.
So who else can be thought of in these terms?
The Hulk. Within us lies rage qwhich turns to utter unconquerable strength when we are pushed unfairly to the edge.
The Fantastic Four. In family there is strength, as well as forgiveness, understanding, support, and the whole is greater than the sum of the parts.
Closely behind the icons, though, come the wish fulfillment wonders.
I wish I could run faster than anybody: the Flash.
I wish I had a magic ring: Green Lantern.
I wish my brain were so smart and powerful I could control the world: Professor X.
I wish I had a suit of armor, a modern one. Iron Man.
And then everybody who can’t be placed into these tiers is an also-ran, even if much loved.
How is the Blue Beetle a wish fulfillment fantasy? His powers don’t speak to our dreams and his back story doesn’t speak to our hearts. That’s why he’ll always be third-rate.
What of Wolverine? Power of rage? Hulk does that better. Healing power? He has to get hurt first, not normally a top wish. Back story? Mysterious figures operated on a pawn when he was awake. Yuuch.
Notice that a lot of what earlier was said was required is missing in this formulation. No mention of flashy costume. No need for a great villain. No need for supporting characters. The heroes are self-defined, complete by virtue of who they are, without any trappings.
Superman can go off into space and still be Superman, even if stripped of his costume.
Spidey can do a whole episode rescuing a cat from a tree.
Hulk just needs a large rock to hulk out on.
We’re willing to spend an issue just with them being them. We might like the other stuff to add some flavor, but in the end it’s just spice on top of our meat.
That’s why it’s next to impossible to add new iconic heroes. Most of the best basic reactions have already been taken. Everything else is a tacit commentary on already existing heroes. Alan Moore has written that scenario a dozen times over, and very well. But you have to settle for critical praise and not a character that will outlive you by decades.