DC Hero Who Used To Be A Big Deal Now Doesn't Seem That Big Anymore

[Thirteen]

He’s not one of my favorite characters but I would say Captain Atom



I would love a Linda Danvers mini by Peter David

That was the nice thing about the early issues of the FALLEN ANGEL series, PAD played it vague enough that one could read the protagonist as a continuation of Matrix Danvers SUPERGIRL in a new city.
Peter David Once Wrote a Supergirl Book… Without DC Comics

Kyle Rayner?

Yup. Once "the next big thing, a GREEN LANTERN like no other" (he had FEAR...and that was a good thing?) and then they realized realized wanted the classic GL back and NOT as a villain.