Disappointed that Jae Hoon isn't in this, as he seemed to be a prominent new legacy character akin to Dong Hwan, Rock, and Hokotumaru.
Personally intrigued by Mr. Big being in this, as he must be in his 60s at this point and his relationship with Geese was considerably less cordial than someone like Billy. Speaking of, would love to see how those two interact. I wonder if Big's English VA will remember that the character is Australian (likely not, if AOF2 was anything to go by).
I only want Wolfgang Krauser to be a secret boss as far as storyline goes. He's the closest thing to SNK's version of Akuma in terms of character morality and motivation, and I hated how he was just a standard final boss with Nightmare Geese being the true final boss in the last 2 installments.