The latter. Previously, the best way to target a specific piece of loot was to stack as many similar armor or weapon types as possible to increase the chances of that dropping. Now, even if you’re the only Rogue or Demon Hunter in your group, you have the same chance as anyone else of seeing an upgrade.
While this does mean it’s possible for a bow to drop in a group without a hunter, the belief is that this rewards groups for playing with a diverse set of classes - as well as the normalizing factor above (mail wearers from the last few years know how hard it is to get loot comparatively).