Hey I had a thought these days that like it's obviously not happening but I'm bringing it as a "what if"/"how cool would it be"
Do y'all remember in E3 2015, Nintendo linked some game announcements in their presentation with Mario Maker gameplay snippets? Like when they were about to show Zelda games, a little sequence of Mario getting a Mystery Mushroom to transform into Link was shown. The same thing happened when they were going to show Fire Emblem (Marth) and Animal Crossing (Isabelle)
Seeing how Mario Maker was the main game of that E3, and Smash is this game this time around, how cool would it be that, sparsed along their presentation, some little 15-second videos were shown announcing Smash characters related to the game that's being shown next? (like Ridley for Metroid Prime 4, Celica/Lyn/FE18 for Fire Emblem, MImikyu/Decidueye/Lycanroc/Eevee for Pokémon, etc), maybe some veterans could be shown instead