Why do dungeons drop crafting materials in place of loot rather than alongside it?

[Prototype909]

Stone Vigil HM Run -

First Boss - Aqueous Whetstone
Second Boss - Aqueous Whetstone x2
Final Boss - Cooking Sherry

Seriously, why can't we just run dungeons and actually have the expectation that we'll actually get some of the new sets instead of "Oh, some crafting material that most people can't even use which isn't even worth that much by itself".