I think a good rule of thumb is this:

Short fight and low damage taken = Fracture is worth it

Long fight and high damage taken = Fracture isn't worth it

For that cooldown you're using Fracture you could be using Stoneskin and by the time you bottom out on TP and start auto-attacking only you'll be at a DPS loss rather than a DPS gain. Fracture is also good for DPS checks like Demon Wall or Titan's heart, but not good for DPS checks like fast conflags. It's also useful for fights where the boss disappears for a short period of time (Siren and the Primals mainly). Fracture basically has it's places, but it's very specific ones.