They've been working well for me...but I've been "exploiting" the new DC rule too. You may be hittting targets too far out of your skill range. Check your skill in the skill caps chart on the wiki to see what character level that is, and then go find mobs that spawn as DC to that level and up. I get .3-.5 skillups that way and the levels come pretty quick. Once I hit ~85 caps, it's dominion time and they cap there just fine (for me at least).