Sean Howe, the author of Marvel Comics: The Untold Story, regularly shares artifacts from Marvel's history on his Tumblr, and this week he posted a memo from 1972 that details where the characters fell in the pecking order--with each ranked as "very important," "important" and "not as important."
Many of Marvel's mainstays are ranked were you'd expect them -- Spider-Man, Hulk, Captain America and Iron Man are all marked as "very important" -- while others are interesting in how their rankings probably would have changed between then and now. The X-Men and Invisible Girl only earn two stars, less than characters like Ka-zar, Dracula, Conan and Doc Savage (those last two being licensed characters that Marvel no longer publishes today), and the same as Red Wolf, who had a short-lived series around that time. Many of the characters on the list also had first issues debut in 1972, including The Cat, Luke Cage's Heroes for Hire, Shanna the She-Devil and Werewolf by Night. There's no exact date on the memo, so there's no telling if it came before or after those titles. Many of them debuted near the end of the year, though, so perhaps it was a precursor to the company's publishing plans. Or maybe Stan Lee just liked to make lists.