I personally think when Sakurai said that he believes, “a change in direction is what’s needed”, he was referring to the game as a whole. You can just focus on adding as many characters as possible, but hen the rest of the game suffers.
Instead, if you already have a big, diverse, well represented roster, you can flesh out other things like single player, stages, items, maybe even stuff like trophies and music.
We’ve seen this in action already with content being added onto simple additions. We could have just gotten Dracula’s Castle, but no. We got stage hazards of different monsters and Dracula himself. It’s not just a stage, it’s an experience.
These are the sorts of additions I think Sakurai is looking for. He’s added more modes that aren’t crap like Tour. They refined other modes like Classic and Squad Strike.
I think fans get too caught up in characters and don’t focus enough on actually being able to play it. Having good characters is good, but will mean nothing is there aren’t new, fantastic ways to play the game as them.