DM has what IM lacks... single target damage. This one thing may be the difference you are seeing. The added tohitt debuff works nice with ice armor. Ice has better AoE than DM, but since you have not made it to Frozen Aura, you do not have a comparison.
YMMV---IMO
Ice Ember
I tryed a ice/ice up to lvl 28, and was getting pretty bored. So I deleted and re-roled as a ice/dm. I am up to lvl 12, but it just seems more enjoyable to me. Course I have the vet power nem staff and sand of mu. So the extra attack from the staff may be what is making the early game better for me.
Also it seems as if they may have buffed ice armor. My ice/ice at this lvl would face plant like crasy. Seems like the -tohit on dm side works well.
However I would like some feedback into, which is a more solid set. I am not looking for what you think is more fun, cuz really you can't tell me what I like. You can add your own personal opinion if you want, I will gladly read. Just looking for which is more steady tanking build and why.... thanks in advance
protector-knight: lvl 50 invun/axe tank
Lillian Brick: lvl 50 stone/stone/pyre tank
Hybrid-knight: lvl 50 db/regen scrap
Vengful-Nature: lvl 50 spines/sr/bod scrap
Element-Wizard: lvl 50 fire/storm/stone troll