You shouldn’t expect any character. That’s a bad mindset that 9 times out of 10 sets you up for disappointment. There’s a difference between wanting and expecting a character.
Well I think it's fair to say that a lot of us were young at the time, and unfortunately we took Waluigi appearing in games for granted.
It wasn't until Mario Kart 7 when Nintendo called him expendable that we begun to notice that Waluigi was on thin ice, but again unfortunately not many caught on to that.
And so Smash 4 happened we were upset but not really as much as in Ultimate, because by then it would be the third time in a row that Waluigi gets shafted while simultaneously both Daisy and P. Plant (a mook that made its first playable appearance, in Smash Bros. no less) got in.
And these 3 and a half years of us fighting for Waluigi to become playable through DLC, while some may think it was all in vain and we gained nothing from it, it finally placed Waluigi (and us) on the map.
Like seriously now the Switch has like 2 more years left in it before the next system rolls out, by then they would have a developed a new Smash game or better yet, an expanded version of Ultimate with the entire roster intact, only now Waluigi is playable alongside whoever they end up choosing for that game.
Maybe go for a quadruple AT upgrade, Waluigi, Isaac, Alucard, and Bomberman.
Then upgrade some Mii costumes like Doomguy, and Dante.
Add Crash and voila, you've got yourself 7 newcomers, the same number of newcomers on the base game of Ultimate.