For what it's worth, there's a "What If...Gwen survived House of M?" issue coming out in December. I wouldn't be surprised if that's meant to test the waters for Gwen's return.
I'm reminded of something one of the writers from the 90s animated Spider-Man animated series said, in regards to why Gwen only had a cameo in an alternate universe episode: they felt that if Gwen was a supporting character she would have to die, and since the censors wouldn't let them do that, they never included her. But now we have Gwen alive and a major character in a new Spider-Man cartoon, and she's a very real presence in the live action, Ultimate (I know she died there, but she got better), Marvel Adventures, and SMLMJ verses. The idea that Gwen must always be "doomed" is slowly dissolving. And of course the Spidey Brain Trust is very fond of the era where Gwen was around. So I think a Gwen resurrection is more possible now that it's ever been.
Is it a good idea? Not to me. I think if people want to revisit the time when Gwen was alive and she, Peter, MJ, Harry and Flash were all young and kickin' it and playing romantic musical chairs, they should have a nice sit-down with the Essential Spider-Man books. Or read/see any of the different Spidey series I mentioned above (well, maybe not Spider-Man 3). But I think it would be a bad direction for 616 Spidey (not that they've listened to me before...)