#3 A Faction war with NXT Call-ups
As stated in the previous entry, there are no other factions to oppose the Shield on Monday Night Raw. There is a simple solution though, tap into the rich well of young talent in NXT. There are plenty of teams and factions in NXT that could rise up to the main roster and make a name for themselves by challenging the Shield.
The Wyatt Family did it in 2014, and they received a huge rub by beating them. Going toe-to-toe with the Shield would have been enough to establish the Wyatt Family, winning should have made their careers, but they were arguably never booked properly again. If a group from NXT, such as SAnitY or the Undisputed Era, debuted by attacking the Shield then their careers would be off to the races. The Shield themselves were NXT call-ups when they debuted, and they could dispand\implode after losing a faction war to the young up-and-comers.
Corey Graves deleted his Tweet! More details HERE.