I don't know how anyone (let alone Sakurai) could top Smash 4 in terms of the roster.
Yeah, the clones are clones but we were already given a reason why they were there. They just became new spots for the roster to fill out when the game was close to completion before its initial release on 3DS and Wii U. Should they be tweaked out more? Hopefully.
Plus, we got some of the most iconic characters in gaming history to join the fight. Mega Man, Pac Man, Sonic, Ryu, Bayonetta, and Cloud fighting against Mario and the gang. Never in our wildest of dreams would this ever happened and it did.
Old and new generations of Nintendo characters (Game and Watch as the oldest, Corrin as the youngest).
It's gonna be hard to top to be honest with you and even getting rid of one character could be a bummer for a lot of fans. Whether it's Rosa, Lucina, Palutena, Little Mac, etc., there will be fans who will be upset, just like when Ice Climbers and Wolf were cut.