Given in the Spider-Man mythos her death impacted him do you think she should ever return in some way? I personally think that it would be good to see her return in an unexpected way as the Green Goblin. I know it sounds crazy but I think it would be a good story arc we always see Norman Osborn or Harry as the Green Goblin I think a good twist would be for a new Green Goblin to pop up and cause trouble for Norman of all people like how Green Goblin caused trouble for Tombstone in Spectacular Spiderman and I'd like to see something like that but done with Norman and a new Goblin.
Ultimately the new Green Goblin could be left as ambiguous for a while being completely chaotic and psychotic like Cletus Kassidy level crazy with Peter completely sure Norman is behind it and then the big twist is that Norman is as clueless who the new Green Goblin is as Peter and the new Green Goblin starts kidnapping people associated with Gwen starting with her killer Norman with all sorts of people between including maybe even Jackal (guy's a creep and cloned Gwen I think so I can see there being a grudge there) and it ends with Peter after a long investigation being the final abductee by the new Goblin who intends to hold a trial for Gwen's death.
Up to the end Peter believes that Norman is behind it and then gets free and everyone escapes as Peter battles the new Goblin and unmasks him only to find out it's not Norman but Gwen whose revealed to be alive some how and completely insane. It comes out someone tried to bring Gwen back from the dead and thought they failed but in fact succeeded and Gwen came back but her mind was completely shattered and had haunting memories of the Green Goblin then one day as she was wandering the city homeless she stumbled on to one of Norman's Green Goblin lairs long abandoned and forgotten some how got exposed to goblin gas and went even more insane ultimately deciding to become the Green Goblin herself.
I'd really like to see Peter react to seeing a crazy Gwen and how he would deal with it especially if she became Green Goblin.
Essentially a situation like this.