The Shield are one of the best things the WWE has going for it at the moment. After their debut at Survivor Series in the Triple Threat WWE Championship Match- interfering to help CM Punk retain the title against Ryback and John Cena, the Shield has dealt out its own brutal form of justice to many of the top faces in the WWE- including Chris Jericho, Sheamus, Ryback, John Cena, Daniel Bryan, Kofi Kingston, Kane and even the Undertaker. There is no doubt that the trio of Dean Ambrose, Seth Rollins and Roman Reigns has a great deal going for it. So you can't blame some people for being tempted to trying to spice up the mix even more by attempting to even more people to the Shield's banner in order to try and generate even more excitement for what is essentially one of the best story arcs the WWE has at the moment. However, there have been many tales of stables going wrong in the past because someone took what was in essence a simple idea and then adding too much to it- leaving it a complex mess that left out much that was cool about it in the first place. So here's 5 reasons to keep the Shield's group a trio.