When they started calling him that, I honestly didn't see it...and I still don't. I think they were just trying to think up a nickname for him and the others, but he didn't stand out as much at the time. Now he does because of his in-ring ability (plus, he's better as a babyface), so if they had waited until now, they probably would have thought of something better for him.
He didn't really have a role in the group. Ambrose is the loose cannon, reigns is the powerhouse, and Rollins is....? Exactly. Just some stupid s**t Cole came up with to give him a role.