The tank classes' damage output is fine. Top-tier DPS can dish out something in the neighborhood of 1200+, where the tanks can't even break 900.
The fact that MCH and BRD can only hit about as hard as tanks only says they need a buff, not that tanks need a nerf.
The fact that MCH and BRD can only hit about as hard as tanks only says they need a buff, not that tanks need a nerf.