I understand where this idea comes from. It's more than understandable to want to see greater context and fluff for the various classes, feats, and other player options. But, from a purchasing standpoint, this proposal can't work.
First, I need to address an underlying assumption, which is that D&D Next will have an ever-growing selection of player options at a rate similar to the past two editions. I'm really hoping that the next edition isn't so exceptions heavy, and that most player concepts can be built right out of the Player's Handbook. After that, I mostly want to see material needed to support different environments, cultures, and game types.
Thus, instead of books like Complete Arcane or Primal Power, I'd prefer books like Manual of the Planes, Heroes of Battle, and Cityscape. These give the various player options the context you're looking for, and also include lots of adventure hooks.
Finally, I have no problem with an adventure providing feats, magic items, or other player options needed to support that adventure. That is, so long as they're really there for that purpose.