I have the same predictions as Leojay.
Ryback, I predict, will fuck himself over by possibly having Cena beat but deciding to continue inflicting punishment on him instead and it allows Cena a bright spot somewhere near the end where Cena capitalizes on Ryback's fuck up and wins the match. Thinking of the best way for Ryback to lose without being 'damaged', I'm thinking a roll up victory where he kicks out of it about half a second too late (since roll ups aren't exactly the most dominant or forceful way of pinning your opponent.) Imagine Ryback, similar to Lesnar last year, has Cena probably beat somewhere during his period of dominance (Lesnar had him beat quite literally last year when he had him pinned but the ref was out) and then he tries charging Cena while Cena lays in the corner but Cena moves at the last second, and Ryback makes head contact with the ring post and then stumbles backwards into a roll up. An alternate way to do it is to have Cena slingshot him into the ring post instead. Since the roll up happens suddenly and doesn't involve Ryback being laid out or forced into submission, it doesn't make him look too weak. He could then destroy Cena after the match and then claim he had Cena beat and wants a rematch, blah blah blah.
I don't think it's implausible though that they could switch the title to Ryback, and The Shield helping him win the belt would be almost poetic. I think though, this scenario would have worked better if it was the actual way Ryback turned heel in the first place instead of him being upset about Cena never having his back. Imagine if they booked this match to be a face/face encounter and then Ryback gets thrown outside the ring, and The Shield then zoom in and attack Cena while he's on spaghetti legs. As Ryback recovers, he just stands there and lets them do the damage without fighting The Shield off at all. Maybe he even enters the ring while they're finishing Cena off and just stands there, obviously not disapproving. He then finishes Cena off to take the title. Obviously, this scenario is out the window now, but it would have worked if they had went about it differently.