It's not MNK's job to kill the plumes, we'd have to turn fists of fire down for that (you don't expect BLMs to kill the plume either, them being resistant to magic). Other classes should be doing this, 1vs1 is what Monks are best at. People are just afraid of replacing one of their BLMs with a MNK because "it's less stable" "not being done that way" or "MNK is not useful in this".