I feel of two minds about it. At the time, it was a big deal in comics storytelling – a major, and at the time permanent, character death in a medium perhaps better known for stories where Superman had a lion head for an issue and where the stakes were low because everything would snap back to the status quo.
However, it’s also the ur-fridging – the violent death of a female character meant to motivate a male hero. And as Gail Simone documented, many comics creators took the surface-level lesson that murdering women for shock value and angst sold comics, rather than the lesson that permanent stakes could drive long-term engagement with stories and characters.
The killing of Gwen Stacy brought with it a seemingly permanent deluge of imitators that limited what female characters could do, what female fans could enjoy, and what female creators could write and draw, and which contributed to a shallow and juvenile
conception of “maturity” and “realism” within the medium.