"MNK is the most popular melee DD, far more popular than DRG." =/= " I'm talking about popular in terms of what is brought to end game content."

And unless your currently weaker via a buff wearing off, you can reapply your dots. Equal damage or greater damage you can reapply. YOU CAN overwrite your dots. The Game will let you. The fact that you don't know this tells me a lot about your Monk.