The biggest issue about this game is how literally every aspect of it can be described as "two steps forward, one step back". They made the game "faster" by increasing the speed of universal movement options and how attacks come out, but nothing was adjusted consistently so now the optimal way to apply pressure is to spam jumps and aerials. They nerfed shields and dodge rolls because of how abusable they were in the previous game, but then they added spot dodge canceling so now smash attack into spot dodge into smash attack is a thing and not worth even trying to contest. Those are just two examples, but the entire game is like this and is a huge reason why anyone who plays this game for long enough ends up hating it. It's like they purely designed things in a vacuum and not how they might fit into the larger game as a whole, most obvious with how some characters were designed at a fundamental level. That's not even to get into stuff like the lack of singleplayer modes, the embarrassingly bad online, and of course how they pretty much gave up trying to balance the game during the latter half of the DLC release cycle with both introducing problematic characters and not adjusting already existing problematic characters at all.

TL;DR: Kid Icarus: Uprising is Sakurai's magnum opus and Super Smash Bros. Ultimate doesn't even come close.