Popping in to say Waluigi has my full support. He may not get his time to shine today, but I'm sure he'll eventually get into Smash. I mean, it's not as if Ultimate was his last chance. He'll continue to remain popular and will continue to make consistent appearances until the next game.
As for moveset, I'll be honest I've never been that much of a fan of utilizing just sports equipment, maybe except the tennis racket since Mario Tennis was his debut. Rather, I feel his moveset should draw from his special, weird abilities he has in the sports games. There's plenty of source material to pull from too: Whiskered Eggplant from Mario Superstar Baseball, midair swimming and Whirluigi from Mario Power Tennis, Moonwalking from Mario Tennis Aces, the weird mechanical arms he has in Mario Sports Mix, thorny vines from Mario Strikers Charged... there's so much to pull from, and offer tons of ways to differentiate from other fighters and make him a truly unique character. And it's not like Smash can't make deep pulls either, considering Piranha Plant's Poison Breath is taken from the Paper Mario series' Putrid Piranhas.
Furthermore, I feel a lot of his attacks and animations should be based on his personality. Look at King K. Rool as an example: he walks with pride and swagger, and flips a switch and runs on all fours like a deranged animal. He's constantly changing his fighting style, going from using Blunderbuss and Crownerang to using down throws and buries, to outsmart his opponent. He rejects any attacks thrown at his belly armor, and counterattacks with a big boxing glove smack. It's like he punishes any opponent for invading his personal, royal space. Who's to say that can't rub off on Waluigi? In addition to these weird abilities, he tries his best to cheat his way to victory. He could run around deceptively fast, and stop on a dime, opposite of Luigi's slippery traction. He could use his long limbs to outrange his sword-abusing opponents. He moonwalks past opponents to dodge their attacks, only to counter them with his own. His taunts and victory animations are degrading, as he aims to make the opponent miserable after he just KO'ed them. He could even have a funny crouch animation like some of the other characters. On the other side of the coin, he could call opponents cheaters when he ends up getting KO'ed. He could throw his hat on the ground and stomp on it for his "clapping" animation, refusing to cheer for the opponent when he should have won.
Waluigi would have zero respect for his opponents, and I think traits like that are what makes a character really fun. Again, look at newcomers like King K. Rool and Incineroar, they're brimming with so much personality throughout their moves and animations, and Waluigi's personality could be utilized greatly in this respect.
