One thing I do hope they do differently for a second Fighters Pass, or just post-Pass DLC in general: reveal all the characters ahead of time.
For a Fighters Pass 2, instead of drip feeding the characters to us one at a time, just make one big cinematic trailer where all the characters are getting invitations to Smash, leaving us just waiting for gameplay presentations like with Hero, Banjo, and Terry.
A good example of what I'm referring to would be
the announcement trailer/cinematic opening for Street Fighter V: Arcade Edition, which revealed all the Season 3 DLC characters ahead of time, and was positively received by fans after the Season 2 DLC characters were just slowly revealed.