Look, I really love the roster that Ultimate has brought us, but a good roster can't do much if the replayability is subpar. Like I said, most of the modes are fun the first time through, but they are not fun to replay. Doesn't help that there's no Boss Rush mode that allows you to pick a character you want to fight them with.
Man, I miss Smash Run and the Mooks you can fight. Even if they don't bring back Smash Run, bringing back the Mooks and using them as parts of Spirit Battles Classic Mode, special World of Light platforming sections similar to Cuphead, have them potentially invade the Smash Battles similar to the enemies in Melee, etc, would make those modes more replayable. Heck, even a Gauntlet/Tower-like mode where you continuously fight against Mooks and Bosses on Smash stages until you are defeated would be great. Fight against Mooks every 9 stages than fight an Assist Trophy or Boss every 10 stages? Sign me up.
Like I absolutely love Smash Ultimate's roster, but I want to do more than just rely on Smash Battles only for my Replayability. That's part of why I have issue with an Ultimate Deluxe is because aside from additional characters, I don't think it would bring more in other content that it honestly needs.