I don't think it's nostalgia, it's more so people wanting others to get another chance since the screenhogs took the spotlight away. I do know where you're coming from though and they're a lot of characters to me that still have a lot to prove from the first generation.
Bridgette, Eva, Justin, and Tyler are still ripe with potential value.
Trent needs a season without Gwen to have more ground and get out of irrelevancy.
Cody needs a Sierra-less season to prove he can make it far on his own.
DJ, Harold, and LeShawna need some redemption after the Team Victory debacle.
Katie and Sadie have yet to return to another season like Eva.
Sierra needs extreme redemption after what happened in All-Stars.
I can see why people want another season with the second and third generation cast, but I was hoping they'd improve these characters and correct them first.