For the same reason that Bioshock Infinite had a more generic "guy with a gun" art. I agree, the art on the left looks better. But if you were someone that didn't know anything about Destiny until you looked at the box, what would it tell you? It looks kind of sci-fi. It maybe takes place in space? But it's showing Earth, so maybe it's only on Earth. As for the type of game or what kind of gameplay to expect, the left art doesn't tell the average Joe anything. The one on the right is more generic, but is also instantly recognizable by the uninitiated. It has guys in futuristic armor and a space-ship sort of thing. So clearly it's sci-fi and takes place in space. One of the guys has some sort of magic thing, so there might be some fantasy elements. And of course, everyone's holding guns, so this game is clearly a shooter. Again, to go back to Bioshock Infinite, I think it was Ken Levine that said box art basically has to cater to the lowest common denominator of consumer, someone who knows nothing about your game before they pick up the box. So you need to be able to tell them everything they need to know in that first image. Otherwise people won't want to learn more about it. Maybe Bungie will provide some alternate cover jackets to print out or put the placeholder art on a special edition.