There have been rumors of the breakup of The Shield for awhile now, and even members of the group have talked about what it will be like when that happens. According to PWS on Oct. 31, the plans for when that breakup occurs will end up with Roman Reigns turning face.
This could make sense, as Reigns is the kind of big powerful wrestler that Vince McMahon loves, and since he is part of the Samoan family that includes The Rock, Yokozuna and Rikishi, he has a back story that could make his turn very interesting. There is also the fact that he is related to the Usos, so that could trigger the eventual turn as well.
Out of the three members of The Shield, Reigns is also best suited for the good guy role. Seth Rollins could play a face, but he is closer to a CM Punk personality than a true baby face role, and Punk has already complained about how hard it is for him to be a convincing face instead of a tweener, which is what he is best at.
As for Dean Ambrose, he might be one of the best villains the WWE will have in the future. He is the closest the WWE has to a Rowdy Roddy Piper styled character and his natural charisma as a heel could make him a top star in the future.
The WWE rumors indicate that this breakup is still a ways off into the future, because the WWE feels The Shield still offers them value as a unit, but with the Wyatt Family moving into the main event scene, the days of The Shield as a top WWE faction might be numbered.