#2. Another major surprise awaits at the Royal Rumble apart from Edge
It's possible that there is an even bigger surprise waiting in store at the Royal Rumble that isn't Edge. While it was hard to beat his return last year, there could be another name that WWE is holding back on as a surprise entrant.
Announcing Edge in advance could be WWE's way of throwing fans off guard for a potentially bigger surprise.
#1. To set up Edge as a potential favorite to win the Royal Rumble
Edge could automatically become one of the favorites to win the Royal Rumble match. While Daniel Bryan is highly-regarded as a favorite, The Rated-R Superstar being in the Royal Rumble adds a whole new element to the match.
There were rumors of Edge having a World Championship match (against Randy Orton) at WrestleMania 37, and it's hard not to see him getting World title No. 12 at some point down the line. Could WWE announcing Edge in advance have to do with him being a favorite to win the Men's Royal Rumble Match?