Stan Lee was definitely the man and injected a human idealism that was lacking in comics at the time. The problem with Lee's work is if you try to read his stuff as an adult. It comes across as goofy most of the time but it was certainly groundbreaking..like the biplane or Model-T. Some writers are timeless though, I can pick up an 80's run of Swamp thing and be utterly amazed at Moore's insight into the human mind. Just like I can pick up an old literary classic by Tolstoy, Shakespeare, or Dostoevesky and be amazed at their work.
True genius is timeless. Stan's concepts, basic emotions, and characters are timeless but his writing isn't.