Yes, the more-or-less permanent end of a semi-important character in 1970s superhero comics was a pretty big step, a landmark that still gets fans in a huff.
But looking back on some of the late-1960s/early 1970s Spider-Man issues, it struck me that Peter Parker's personal life isn't too far removed from that of Archie Andrews. When Gwen Stacy and Mary Jane Watson are standing around together in the same panel, it's hard not to think of Betty and Veronica from Archie comics. Check out the pics below – aside from hair color/style, they're practically twins!
So instead of the agonizing choice between a blonde and a brunette, the hero must choose between a blonde and a redhead. Progress!