I say keep both faces and keep building in that and in two years flip the switch so that whenever one of them turns there's enough emotional equity that it's an actual event instead of just another ho hum run of the mill heel turn.

Plus everyone hates Sheamus and he's dann near the perfect guy to help Reigns get over the hump with certain fans and it's worth trying to build him as a face right now. It may not work but i say stay the course and see how this plays out.