Well, I really didn't expect a Smash announcement at Game Awards, so I didn't bother watching it live (it was broadcasted at the worst moment of the night in Europe). So when I did a Google search this morning and saw "Joken is coming to Smash" I was utterly confused. However the main reason why I didn't expect a new character this soon is because it likely wouldn't be far in development, and with no gameplay footage yet it suggests that the character himself is not far enough in development to be shown yet, so I was half right at the end.
Even though I'm not very familiar with the series myself I vaguely remember briefly considering a Persona character as a possibility at some point due to it being one of Sega's most famous franchises, and to be fair with how liberal Smash has gone with third-parties at this point I reached the point where I'm not really surprised by character choices anymore... but after seeing people's reaction to this it's actually a pretty incredible addition when I think about it, being from a recent PlayStation exclusive game, combining the characteristics of both Cloud and Bayonetta which were reasons why they were unexpected for Smash 4 DLC.
Now I'm waiting for the gameplay trailer, but unlike Mewtwo we will have no idea of what his accurate moveset will be like until that point. First time Smash really lets us speculate about the moveset even though he has already been confirmed. I also hope the animated trailer means we will have at least some unique animations for DLC character announcements this time. I'm not sure we can expect actual CGI movies like we did with Ultimate newcomers, but for this animation at least the part with the silhouette of Smash characters is original.