Final Fantasy desperately needs one; like, its current utilization is just plain insultingly pathetic: it's the single most expansive franchise used in Smash (yes, I would argue bigger than Mario), and yet it has a character with a stage, and absolutely nothing else.

Also because you mentioned it, Metal Slug's absence should have been the big controversy about SNK's contribution, not Mai.

I genuinely wish they would add new assists in an update, and am curious as to how much developer work a set of, say, 8-10 of them would take compared to a fighter+stage update. I do understand that it's not something most people would specifically pay for; note that for the entire time I've been participating in discussions about it, I've always viewed the game from the perspective of an observer who is simply interested in how many icons can be included and implemented, not a player.

I also find it odd that they brought back most of the preexisting assists for Ultimate, but left out several (and not just the ones that became fighters); Custom Robo, Kat-Ana and Elec Man come to mind.