#4 The Return of Bludgeon Brothers

Rowan and Harper were the dominant tag teams on SmackDown, unlike The Usos and The New Day, The Bludgeon Brothers were big, scary, and chaotic.
They soon won the tag titles by beating The Usos. However, with Rowan getting injured, they had to drop the belts and have taken time off TV.
At Survivor Series, five teams from Raw are scheduled to face five teams from SmackDown Live in an elimination match, and that would be the perfect opportunity to reintroduce The Bludgeon Brothers, and have them run riot during the match.
#3 Ronda Rousey's first loss

Ever since Ronda Rousey made her WWE debut at WrestleMania, she has been booked as the most dominant force in the company, and it does make sense to build the division around her, considering she was the UFC bantamweight champion for years.
It won't be long before WWE fans get tired of watching Ronda manhandle her opponents, because Ronda has made the other female talent look weak.
With a loss to Charlotte at Survivor Series, WWE could also tweak Ronda's character to make her gimmick more interesting.