I've been thinking about single player content for this new Smash game. I hope Sakurai doesn't think single player isn't important because he brought back every character and brought back 80+ stages and that's good enough. The reason I was mostly disappointed in Smash Wii U was there was no fun/compelling single player content. Say what you want about Subspace Emissary but at least it was ambitious and there were SOME fun things about it. It extended the life of Brawl to me MUCH more than Wii U did..
I seriously hope we get something more akin to Melee's Adventure mode but maybe a little more fleshed out. Where we run through Nintendo themed worlds beat up classic Nintendo enemies they can port most of the assests from 3DS Smash Run and have a story. It doesn't have to try to be deep or have an abundance of cutscenes since Sakurai doesn't want to do that again. Maybe have an opening cutscene and an end cutscene. Let the story be about Nintendo villains joining forces to take over the world or something. Like have Ridley, Bowser, K.Rool, Ganondorf, Wolf, Wario, Mewtwo, Dark Pit, Dedede, Bowser Jr. as the main antagonists. Like have each of them be the "boss" of each heroes level and then once you beat them in like a 1v1 2 stock battle you unlock them in game. Sakurai did state that the roster you start off will be small (the original 8) and you will constantly unlock more characters and I think this would be a fun and interesting way of doing it. Let's say you start the Adventure with Mario and throughout the Adventure you constantly unlock new fighters to join you and you then (like subspace) can swap between them but also incorporate the mechanic from Smash Tour where during the "boss battles" if you get knocked out with Mario let's say Diddy appears and then you use Diddy. Essentially different characters are your lives. They can even have mini-bosses throughout the stages for characters like Petey Piranha, King Boo, Marx, Kraid, Hades, Andross, Tiki Tong or Lord Fredrik, The Broodals, Ghirahim, etc. You know characters who don't stand a chance of being playable. Of course with it being a Switch game the Adventure mode has co-op and I'm also thinking incorporating the Uprising/Classic Mode difficulty scale feature so you can replay the Adventure multiple times if you want on varying difficulties. I'm also thinking this Adventure mode would be around 6 hours long to complete.
Obviously I'm just spit-balling here but would love more single player content in this game. I know this was kinda off-topic but K.Rool would be one of the main antagonists of this hypothetical mode. I would love to see like the DK world have Kritters, Klaptraps, Zingers, Tikis, Snowmads, Gnawtys just all together.