With the amount of utility and damage the monk brings currently, before patch 5.1, there is no real reason to bring any other melee besides maybe Dragoon as a Second melee. Sam doesn't do enough damage. Nin, though recently buffed, still has it's fair share of issues. The main one of which is trick attack.

The reason Nin has been so low on DPS was because of it's utility. Monk has great personal and raid utility, yet is top DPS.

Even though I personally dont like SAM in any regard I understand how it should be balanced because it's kit is 100% selfish. Dragoon I believed is balanced as the #2 melee DPS. Monk and Nin should be interchangeable because of the utilities they can/should provide.

But enough about me. If you think you can change my mind try it.