Respectfully disagree about accuracy. I count the amount of times I've seen Energy Drain miss dreadnaught on a single hand in the 15+ T4 runs I've participated in and it's rare to see Miasma miss, and Holy stops things dead in their tracks in P1 and P4. I can consistently land Stone II on soldiers in P2 once half the adds are dead and fairly regularly on the Dreadnaught. However, I notice a significant miss rate against the nodes in T2. I think T4 has a lower accuracy requirement compared to the other Turns due to the fact it's a "Kill all trash as fast as possible" turn.
But like you said, if the DPS can't kill T4 even with the increased 10% damage, yeah, something is horribly wrong with your DPS.