I've see some people mention Spirits as a boss rush mode and honestly, I can't see there being a section on the main menu as big as "Smash" just for boss rush. I think there has to be a melee-esque adventure mode tie in.
I may be wrong but that's my realistic wish.
Also, just because something is trased doesn't mean it will deliver an obvious message *ahemRidley'sshadowahem*
Gotta say, as a Ridley fan who regrets chosing to be so blind, these teases aren't at all comparable.
Ridley's shadow was shown immediately after talking about stage bosses, on a stage where it would make sense for him to be a boss. The Ridley fan base was just choosing to be ignorant.
This was Sakurai flat out teasing a mode and going HMMmmMMmMMM what's this oops can't talk about it just yet
. Like I said while I'm not expecting a story mode, I think it's fair to be dissapointed if it's Smash Tour 2 lol