#1. It doesn't help Authors of Pain get the required leverage they need
Authors of Pain made their presence felt a few weeks ago in a big way, and they are still making waves among the WWE Universe. In case Seth Rollins wins the US Title, AoP would be restricted to a protector's role, which would be similar to J&J's role during Rollins' first WWE Championship reign.
Putting a title on Rollins would limit the duo and would keep them from showcasing their brute strength in RAW's Tag Team Division. If Seth Rollins doesn't win the title, we could see them inflict pain on their opponents and become the major focus of the new faction. This way AoP will not only become more aggressive, but also more valuable to the overall program.
In case AoP wins the tag team titles from The Viking Raiders while Seth wins the US title from Rey Mysterio, we can rest assured that it would build them further, as well as create an opportunity for other tag teams to shine.
A championship reign that commences at Royal Rumble and ends at the Grandest Stage of Them All would be a great way to keep AoP and Seth Rollins at the epicenter of everything on RAW. Rollins' success, however, should not come at the expense of the up and coming duo's rise to the top of RAW's Tag Team Division.