You can never truly know a game until you play it.
Seraph, from Matrix Reloaded
Okay, so I'm paraphrasing, but the point stands. Right now we don't know much about Destiny, but it might be pretty difficult to say we know anything at all. I'm starting to get a sort of pleasant feeling of deja vu, and wondering what it was we thought we knew about Halo when it was first revealed. Our first glance at the game back then was more substantial back in the summer of 1999, when Steve Jobs welcomed Jason Jones on stage to show Halo running live, in real time, using OpenGL, on a Macintosh. He then said it was coming out on PCs and Macs next year.
The rest is history.
Perhaps Bungie showed more of Halo back then than of Destiny now because they honestly thought they were closer to releasing Halo than they really were. Possibly they felt they had to generate some hype for the game. Despite being an award-winning cross-platform developer, it's hard to say that Bungie commanded the kind of attention before that game's release in the Macintosh gaming market that they have occupied in the console world ever since. Now, independent from Microsoft, without the need to serve the well being of the Xbox platform over and above all else, the players on Sony's platform may now be their thrall as well, and after that, who knows, perhaps those on Macs, Windows, and even Linux, iOS and Android. Bungie would appear to have big plans for Destiny.
It's not the first time Bungie's had big plans, though, and things have a way of taking on a life of their own. In particular, some of Bungie's plans for Destiny remind me of what I always guessed were Bungie's original plans for Halo...