This is assuming the melee has no idea what they are doing and single targeting an easily AoEable pack.

Not using AoE rotations is ridiculous, melee or not. Even though they have the worst AoE in the game, a NIN using Doton+DB is still higher DPS on more than 3 mobs than single targeting.

Better topic: Dear melee DPS: learn how to AoE and make a reasonable contribution to the run.