The way I see it, Natalya can't be an option only for the simple reason of how underwhelming it would turn out to be as a revelation. No offense to Natty but, I mean, all this hype about the mystery partner, only to reveal Natalya? Nah, if WWE is hyping this up the way they are, it has to be a fresh face, somebody we haven't seen in a while.
As far as Paige is concerned, while it would definetely create a huge buzz, I'm not sure WWE are willing to put her on the blue brand so long as the New Day are on there for, well, pretty obvious reasons. They may be able to control what signs the fans bring to each event and even somewhat mess with the sounds depending on what they want us or don't want us to hear, but I don't think they'd be able to control whatever smart ass chants were to start. And what they gonna do? Throw everybody out? That ain't a solution.
Now, granted, the argument could be that RAW already got Asuka so it would make more sense for SD to add Paige if they want to have somewhat of a balance on both brands but, again, that will all depend on how WWE decides to approach this...
In regards to Brie Bella, being it's been such a long time since we last saw her, it would certainly be a very pleasant surprise but between their new born child (is she even fit for a return?) and the question marks around Bryan's future in the WWE, I'm not so sure they'd bring her back just yet.
My early guess? Niki Bella....
