A compelling story. It's all I've ever wanted, and is my biggest complaint. So many people jump up and down and say "what about the grimwar". Sure, there is some good stuff in there, but don't you think that the game should be the vehicle for its own story? Evry grimwar card I've read has only stood out like a sore thumb as a missed opportunity to make the actual game interesting. It's all there... they just had to put it in the game. Second thing that that needs improvement is the loot table and the loot mechanics. We need vastly more loot, and a better system for rewarding, and upgrading it. We need 20 times more legendaries, 10 times more exotics, 10 times more boss specific item drops.