Whedon's comic-book dork bona fides are all over "Buffy" like a rash, but more importantly, Astonishing is a complete love letter to the Claremont years from the word "go," from the moment Kitty walks into the mansion in issue #1.
You could accuse Whedon of maybe not reading any X-Men comics after maybe #200 or so, but you cannot accuse him of not doing the research. He regressed; he did not ignore.