Well put Kev.... one thing I will add, the whole superhero vs "just weird stuff" theme does not fit.
To say :"Remaining consistent with the Greek mythology ages of metal, the Bronze Age (as well as a subsequent Iron Age) ought to start with superheroes, not Conan and Swamp Thing." " is off the mark.
The books were experimental, and yes, even weird, but the whole point was they WERE superheroes. Conan, Swamp Thing, Werewolf by Night, Ghost Rider...in a way, these were indeed heroes. That is what makes Conan #1 the starting point of the age. He showed that heroes don't have to be super-powered do-gooders in colored tights. They could be flawed (even very flawed, nearly criminal,or cursed) people who just kind of fall into a hero-ish role, whether they like it or not. That "flawed, reluctant hero"concept fell into the regular hero books in the form of drug abuse, alcohol abuse, and anti-heroes.