Honestly, seeing these incredibly weird spirit events come out every other week or so has me more excited than the actual DLC reveals to come. Having all of these franchises in one game really just cements Smash as the greatest celebration of video games the world has to offer. Plus, Smash has always been a series very heavily rooted in Japanese game series, so seeing the franchise reach out a bit more to the west is always nice to see.
I really hope we continue to keep getting spirit events for franchises that would've been considered absolutely impossible a few years ago. Just going down the list of recent and upcoming Switch releases, I think series like Streets of Rage, Saints Row, Rune Factory, Puzzle and Dragons, Atelier, Frogger, Five Nights at Freddy's, Super Monkey Ball, Witcher, and Overwatch are all definitely notable enough to warrant a spirit event or a Mii Costume at the very least.