The problem is a lot of the things he did with Gwen were things he had done before with Betty. (He just took things to the next level with Gwen since she was the love interest a lot longer.)
The entire "loves Peter but hates Spider-Man" thing was done with Betty. Even the death of Gwen's father invokes the death of Betty's brother (right down to the use of Dr. Octopus being inadvertently responsible.)
It's understand why Conway really wasn't attracted to Gwen as a character. And the decision to kill her wasn't Conway's alone. Jazzy John Romita and Rascally Roy Thomas were also heavily involved. And this decision is what gave Norman his claim to fame.