Positive: Helps get The WWE Universe behind Roman Reigns
Let's be honest here. the only ways WWE was going to get away with making Roman Reigns the top guy was if they brought back The Shield during his title run. Not only did it force The WWE Universe into either rooting against Reigns and against The Shield or rooting for them as a unit.
Of course, The WWE Universe eventually relented and started to throw their support behind Reigns and The Shield as collective, but there are some detractors that the company is going to have to win over in the coming months. Furthermore, WWE is going to have to make sure to build Reigns as an individual so he doesn't lose all his momentum once The Shield splits.