I don't see why you couldn't do Golden Age with more depth, the main reason it was 3 color and shallow was because it was the times and the readership was either younger, or the world didn't want to be reminded every minute that it's a nasty, evil and unfair world. For much the same reasons that The Pulps were so popular at the time, it was as much an escape from the reality of the world as a cheap form of entertainment for it's time to cost ratio. I mean, for a nickle in the early 30's, you got a couple or three hours of adventure and out of this world fantasy of a place where good won over evil and men (and women) of morals were respected.
I don't have a problem with Silver Age, it's a fine middle ground in my eyes, some of our most famous heroes came from Silver Age and have simply changed with the times. But, you still had a clear line between good and evil and even those who skirted that line had some reason to do so.
Sadly, I've never liked the stuff very much in Iron or after. Again, if I want to see the world as it is, I can look out the window... figuratively speaking, or turn on the news. Heroes don't seem so much like heroes anymore so much as powerful people who as often as not sink to the level of those who they fight to maybe get balance in their little part of the world. I'm not against it, but I still tend to play characters with a strong moral, if not sexual compass and want to make the world a better place by removing threats to it via law and order.... If you want to be serious about, do the police ever actually try someone that Superman or spider man left hanging around the stationhouse with a note, "These are bad guys." A little unreality is nessessary simply to have a super-hero... so why crawl in the dirt if you don't have to?
Anyway, There isn't any law that says that a particular age must be restricted to this or that, the great thing about role-playing is that you can pretty much create your own feel.