My understanding is that augment slots aren't suppose to be a top-tier ability, it's for fitting in a necessary gear attribute that you don't prioritize high enough to dedicate an actual piece of gear to. If you're a DC caster you should get an item with a primary focus on DCs (caster stick with major focus on it, like staff of the necromancer or twilight). The slot would be for a secondary goal of the character, like a necromancy focused PM that also wants to do some enchantment.
That said I agree that they yellow slots are weak. HP (of the false life variety) should be moved from blue to yellow, and some other randomish qualties should be added (I mentioned melee alacity before, deathblock is another good one, 20% blurry should be added, I don't know about FoM as that's a rare quality on any item and to strong for a slot)