Riskman
Smash Apprentice
There seem to be multiple different versions of the direct, one without the caption 'Other Bosses' and one with it. Still, Sakurai did say that other bosses appear on other stages so I agree that the whole 'It was the Yellow Devil section' argument is a little bit silly.It wasn't the "Yellow devil" section, rewatch it, he said there are "Other bosses" and it showed the shadow.
Nobody ever said that that was the finished thing, hence why the pyrosphere was absent during the demo.
However, I still feel that Sakurai is holding out on something. It isn't unlike him to word something ambiguously, on purpose or thanks to translation, causing stuff like this to happen. What is happening here pretty much happened with Ness in Brawl. It also isn't unlike him to toy with the fanbase either, with instances like Ganon not using his sword and the 'Zero Suit Samus stunt'.