#4 The Shield Vs. WWE's Bullet Club

Since there is no faction on the main roster that can go toe-to-toe against the Shield, WWE could possibly align two of the most gifted performers in the entire industry, Finn Balor and A.J. Styles.
While both the superstars are currently enjoying their time on different brands, the creative team could present something phenomenal here by booking a cross-over alliance to rule both the brands.
Did you know a top WWE Superstar just wrestled outside the company? More details HERE
Finn Balor's heel turn could seriously alter his chances to grab the brass ring once again, and impress Vince McMahon by forming the Bullet Club that is exclusive to WWE.
This also invites the possibility of a future collision between the Phenomenal One and the Demon King, and will also catapult Luke Gallows and Karl Anderson to a different stratosphere of performers on the main roster.