2.Selling parts of the game digitally
You are a single player gamer / someone who would like to play just the campaign mode of a game, without any multiplayer component, but you still have to spend 39.99/59.99 for the whole package that includes the part that you don't want.
You are someone who loves multiplayer action, don't bother with campaign mode, but you still need to pay the full price for the full package.
Two opposite situations, the same problem: forcing the customer to buy a part of the game he doesn't want / like.
And, because of that, there are customers that decide to not buy that game, because there's a part that they don't consider as valuable.
The solution to this would be allowing developers to sell parts of their games on the digital store. Selling the campaign mode for a specific price and the multiplayer mode for another specific price would enlarge the customer base for many titles. Giving customers as much options as possible (without doing the opposite error: giving too much options, leaving him confused about what to do) is the key. It would mean further pricing flexibility, rise in digital spending, rise in game sales in general.
P.S. COD at 39.99/59.99 --> each part NOT for 19.99/29.99, but for a little more, like 24.99/34.99, in order to make the complete package appear as a bundle at a discounted price, and so letting it remain attractive for all the others who don't bother in paying even for components they don't care too much.