#4 A cliffhanger leading into next week
Ultimately, we live in a world where nothing is must-see television anymore. Even the best match can be watched at one's convenience with the availability of streaming platforms. There are way too many distractions for a casual viewer, because of the abundance of options available for fans.
Cliffhangers are the only way to keep an audience member engaged from one week to the next. WWE has achieved this in a sense with The Fiend, where you don't know who he will attack next. They have also left us with questions after Seth Rollins and Braun Strowman became the RAW Tag Team Champions.
But neither of those hooks even remotely compare to what WWE is attempting to do with the Roman Reigns angle and the case of the mystery attacker. It makes sense in a way because Roman Reigns is the biggest star that the company boasts.