MNK can easyly sustain AoE damage with an easy rotation of "Arm of the Destroyer" > "Twin Snakes"/"True Strike" > "Rockbreaker"; with "Invigorate" and "Purification" they can refill their TP and they don't run dry easy. Also "Elixier Field" and "Howling Fist" are good AoE DPS. And if the MNK is not braindead he can sustain 3k+ DPS on a fullpull in Xelphatol, it is less then a SMN and not as sustainable like a BLM but can challenge a BRD easyly in DPS only lacks in sustain, but if you need more TP then "Purification" and "Invigorate" gives you, you should question the overall party DPS.