What would the comics have been like if Gwen had lived?

[Mister Mets]

I think Gwen's death had far reaching consequences throughout comics. It can be argued that it was one of the precursors for the Dark Age of the 80s and the 90s. Without it, it can be argued that those may have happened a bit later than they did.

Maybe. Other love interests had been killed off, including Iron Man's girlfriend Janice Cord in a comic published before The Night Gwen Stacy Died. It also happened with James Bond in Her Majesty's Secret Service (the 1969 film and 1963 book.)