Retaliator is linked to damage taken to the shield, full damage not the reduced value that bleeds through. Each class has its own Retaliator value.
For Dreads its 0.48s / 1k damage to the shields, per module, so a possible total of 4x0.48s = 1.92s cd reduction per 1k damage to the shield.
Now 1k damage is not a lot. So lets look at a base T4 Goliath, direct impact, no module amper, at 20k damage, this means 20x 0.48s = 9.6s of cd reduction per module, with a "bleed" through of 7k damage to the hull.
Summed up: Don't shoot Dreads if you see a green clock symbol in their buff list when they take damage to the shields. You will just help them spam their modules like crazy.