Well, we all know Sakurai meant Ridley at that time. ^^ But the way he says it can mean literally anything. Everything from 'Will show up every now and then as a hazard', or 'Will be announced anytime now!'. Etc etc. I still Think Sakurai knows very well people wants Ridley, and teases us to Think he won't be in, to make a big(lol) impact when finally shown. I mean, he HAS been teasing Ridley a LOT. I really don't Think he would do that if he was just a hazard. That would be plain-out mean. It was mean when he said ZSS was gone as well, but he came Clean mere seconds after, so that's ok. ^^
Of course he's not confirmed or so, and I don't mean to start a Ridley discussion here (my bad), but really, I just don't Think Sakurai would do all this, hinting at him, showing his shadow, talking about bosses at the same time without actually saying he IS a boss, as to 'make us Think he is, in that way, so that he actually never lied about it'. Sakurai is certanly a troll here!
What if there's a newcomer trailer, and Ridley flies in. BOOM, it's actually Zoroark!
;(