Bungie didn't just promise us the world, they promised us a galaxy.
The developers' first post-Halo IP was hyped to the point it could never possibly fail, by the press, developers, publishers, and fans. An exciting new series from the creators of Halo with the full backing of a huge publisher - why wouldn't you be excited?
Bungie didn't help temper expectations either. Bungie COO Pete Parsons said in an interview last year: "We like to tell big stories and we want people to put the Destiny universe on the same shelf they put Lord of the Rings, Harry Potter, or Star Wars."