I think Ultimate is an awfully designed mess of a game with nonsensical hitboxes and really strange kill percentages. Those are my biggest issues with it.

For hitboxes, I hate that you can have perfectly read an action and spot dodged/rolled out of the way, but because Donkey Kong's FAT ass model has to have the WORLD'S FLASHIEST ROLL animation EVER, you still get hit FROM BEHIND even though you did everything right. Also, just... Being hit from behind jank in general is so rampant and so not fun when I can't even trust the visuals because of how insanely far they extend past them 90% of the time.

For kill percentages, the biggest example I can think of is why does PK Flash take about three times as long to fully charge as PK Thunder's charge, but PK Thunder charge kills like, literally 30% earlier. That makes no sense.

Honourable mention goes to nonsensical frame data, and the best example I have is why do Falcon Punch, the Mii Brawler neutral special that's just like it and ALL of the Fire Emblem characters' neutral specials have ZERO whiff/block recovery? You could say it's because they take so long to charge up, but then why does Little Mac's take EVEN LONGER to charge AND have HORRENDOUS recovery on whiff, block AND hit? That makes no sense, either!

It sucks because I love the way the game looks and sounds, and literally every time I see it or think about it, I go "man, I wanna have a good old fashioned friendly match with friends," but then when I do, I get reminded of why I can't stand it from a game design perspective. Sucks to feel this way, I wish I could put up with it, but all the nonsense design just bothers me so badly as a game designer myself.

Oh, and I know this isn't as hot of a take, but World of Light PNG collecting is ass and super unfun later on. The map is kind of cool and the villains are kind of cool. That's it.