My unpopular opinion (I think it's unpopular) is that they should do this:
Mario: Remove Dr. Mario and Daisy. Add King Boo, Paper Mario and DImentio
DK: Add Funky, Dixie, and Kranky
Zelda: Toon Zelda as an echo, Linkle, and Impa
Metroid: Sylux
Yoshi: Yarn Yoshi as an echo, Kamek
Kirby: BWD, Mgolor, Marx, Adeline and Ribbon, Queen Sectonia
StarFox: Ok for now
Pokemon: Remove Greninja, replace him with Decidueye
Earthbound: Add Porky, Masked man, and Ninten as an Echo
F-Zero: Black Shadow as an echo
FE: Remove Corrin
WarioWare: Add Ashley
Splatoon: Octoling as an echo