I could see the smash direct being something like this
Start with Incineroar fighting Ken revealing both
Sakurai comes on and shows the whole launch roster of 72 in the character select select screen
Transitions into showing the new all star mode, followed by the rest of the options under games & more like homerun contest, stage builder, and ends on the new trophy game
Transition into introducing trophies "the ultimate trophy list" showing some off and ending on one that is a boss character
Transition into spirits mode, spend a great deal of time showing how the mode works, showing how it's the main way to unlock characters
Transition into further expanding on the games online options and how the side bar helps you to better connect with friends or rivals online
Sakurai does his "I hope everyone is looking forward to playing the game" schtick, then does a one last thing, dlc character SE rep
I can see the above taking up about the same length as the last smash direct. Games and more + spirits mode have largely been kept hidden, same with online stuff.