So I've been looking through my augment hoard and noticed a few things...
Elemental damage augments give more than Cannith Crafted (ie ML8 augment = 3d6 while ML8 CC = 2d6, ml20 augment = 6d6 while ml20 CC = 4d6)
Elemental resistance augments still use the old values so ML16 = 25 but ML16 CC = 30.
ML 8 Resistance augment = +5 but ML8 CC = +4, however ML4 on both = +3.
Spell Power, Stat, and Skill augments seem to be the same as CC (except ML1 SP = 30 while CC = 38).
So I guess you should only craft a damage proc on a weapon if it is not acid, cold, electric, or fire.