Reasons why I think the Smash Prophet is right:
- He listed Villager, when the prevailing wisdom of the time said Sakurai wouldn't include an AC character as per his past comments
- He listed Wii Fit Trainer, a character NOBODY saw coming
- He listed Mega Man, and of course, Mega Man was revealed
- He posted his list on GAF the night before the Direct, and didn't edit it after the fact
- He told Gemantsu his list of six E3 reveals a week before the Direct
- There is a "Smash Circuit" boxing arena; much like "Smashville" as the AC stage, I suspect this is Little Mac's stage
- There's symmetry to these reveals: Two "character" newcomers (Villager, Little Mac), two third-party mascots (Mega Man, Pac-Man), two "Wii" characters (Wii Fit Trainer, Mii).
- Wii Fit Trainer's reveal coming AFTER Villager and Mega Man, in her own separate video, suggests other individual trailers may be lined up for their own separate reveals
As for why Nintendo might do such a thing... Perhaps the plan would be to give us three newcomers on the first day, give us the second day to talk about them, and then close out the event with renewed momentum with the reveal of three more newcomers.
Sakurai's in town, he'd probably like to see the reactions. He's not one to NOT outdo himself; he always goes above and beyond the call of duty. He brought five newcomers to Brawl's debut; six newcomers (including two third-party) would certainly do the trick here.
So... I don't know. I'm cautiously optimistic.