I hope that regardless the characters of the next fighters pass, Sakurai and his team continues to include new universes into the game via Mii Costumes or spirits. During the last FP, we got 5 new/returning Mii Costumes per character, so we will get around 30 new ones thanks for the second FP.
For example; imagine that they include a new fighting game character like someone from Tekken, in addition to mii costumes from other fighting game IPs like Soul Calibur, Dead or Alive, Guilty Gear and/or Mortal Kombat. Every series need at least their tiny representation in Smash Ultimate so it can be called the ultimate tribute to videogame history.