Is fracture even worth using as a DRG?

[Jarinolde]

Ah sorry, just looked it up and saw it's an 18 second dot, not 15.

So that's 5 instances of dot damage? or is it 6? Do you get 1 dot tick immediately when you use the ability (A 100 potency hit plus a single 20 potency dot tick at the same time)? Otherwise this would make it a 200 potency attack overall.

That's not how DoTs work, but still with the way they currently work yes, you'll on average only get about 5 ticks from it.