All the ridiculous twists and controversies of this year make last year look amazing in comparison. That said, I'd be very surprised if any one other than Amelia got voted back, and, I can see her walking it. She just needs to give one amazing performance and everyone will be praising this new twist for rectifying the problem caused by the twist in week one. Everyone will be yelling "How could Kelly have let her go?!" Or something like that.
At the end of the day, it's just a TV show, and the contestants have been a little... underwhelming this year. If this twist brings back someone with a bit of spark and charisma, who is entertaining to watch, then I'm all for it.