I know this is a question that comes up often, but I still find it interesting to talk about: what changes would you guys like to see in the veterans' movesets? These changes can range from simple buffs/nerfs, outright new moves, or even wholly revamped movesets.
In Ultimate we didn't really see anyone get a full on rework, like Brawl Falco and Smash 4 Pit and Bowser. However, we did get a lot of quality of life changes that I don't think people appreciate as much as they should. Zelda and Sheik's Side Specials no longer putting them in freefall, Link's Remote Bomb, Ganondorf's sword smashes, Luigi's new tether grab with the Poltergust, Pikachu's new discharge N-air, Rosalina's new Star Spin-esque Nair, the list goes on and on. We also got some juicy animation/visual tweaks that made me really happy, such as Mario's Cape finally being, you know, a cape over his shoulder, instead of some sheet he swings around. I also love how DK carries opponents over his shoulder for cargo throw, like the kidnapped Pauline in the original Arcade game. Or how Bowser's Jab 1 is now a sumo-style palm strike. I'm also a big fan of Marth's new forward throw. Details like these make the characters feel fresh and new each time, even if they're as small as the ones listed above.
If it were up to me, we'd see a lot more of that attention to detail and refinement in every character. What Ultimate did is a great first step, but I'd love to see it taken even further. Give every fighter new visual flair, new animations, cool new attacks (where it fits, of course. I hate shoehorned references). Some need it because they're visually boring (DK and Yoshi come to mind), others need it because they're kinda out of character (Bowser, Samus and Wario come to mind) and others need it because they're just mechanically broken (of course, Steve and Sonic come to mind).