Apparently, Chris Claremont has created 703 Marvel characters; both he and Peter David have done a good job of incorporating different types of diversity into their books (Storm, Dani, Rictor, Sunspot, Monet, etc). Interesting article on both for those who want to read it.
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"Claremont said his two key Marvel experiences were picking up a copy of "Fantastic Four" #48 when he was in high school, in which Stan Lee and Jack Kirby introduced the Watcher during "The Coming of Galactus," and then being hired to work at Marvel shortly after getting out of college. He said that for years, he was cribbing script style off that Galactus story, which not only threw tons of new characters on the table in three issues, but then wrapped the action within the first 12 pages of the final issue in order to shift to character subplots like Johnny Storm going to college. That lack of wasted story space in service of story beats guided Claremont.
"That's why 'Days of Future Past' only runs two issues – because that's all it needed," said the writer, adding that the difference between his comic and the recent film was that "one cost $25,000 and one cost $250 million." The legendary X-Men writer went on to say that the influence of that story stretched farther than he ever imagined..."
http://www.comicbookresources.com/?p...ticle&id=53459