#1 Another mystery
Remember Roman Reigns' mystery attacker?
While that ultimately didn't go anywhere and just served to break up the team of Erick Rowan and Daniel Bryan, it was still one of the most compelling storylines the company had done in a while. In fact, between the non-stop cliff hangers, to the company invoking imagery from The Attitude Era to pull it off, this was one of their best moves.
With that being said and the company seeming to lack that kind of storyline in their weekly programming, the disappearance of Daniel Bryan is a great mystery to get fans hooked on. It even seems to have expanded the lore and powers of The Fiend, which is a huge service to his overall character.
The Fiend's world-building aside, this is an excellent way to get fans invested in the upcoming episodes of Friday Night SmackDown and brings a cartoonish aspect to the overall storyline. It's essentially this perfect mix of varying storylines all sewn together into one coherent and creepy story.
Where did Daniel Bryan go? What kind of state will fans find him in once he does eventually reappear? These are all questions the WWE Universe is asking themselves after the series of events that have played out and it's going to generate a lot of interest in the long-term.