It does not make sense for a +6 ability augment to be Min Level 20, when you can find min level 11 gear with the same stat.
I suggest reducing the level requirement by 4.
+8 ability Min level 24
+7 ability Min level 20
+6 ability Min level 16
+5 ability Min level 12
etc
A similar change could be made with the skill augments. I believe that a reduction of 4 levels still gives the edge to random loot, but offers a bit more use of augments. Also it would allow for another level of augment at level 28