Level 44 Dragon Advance- Every attack the monk makes has a chance to increase hate with the attacked target.
(Very useful for monks who tank as it helps them keep agro. Also, not replaced until level 59 by Infuriating Tranquility, so it has longevity. Took this one.) By rotating targets in an encounter and hitting each a few times, you can easily maintain firm control when you have this ability upgraded. This also makes it much easier to grab back any lost aggro as you can hit your lunging mongoose to drop a full extra taunt's worth of threat onto any peels in addition to using your taunts as they cycle.
The replacement is Storm Stance at lv 56. The adept 1 Storm Stance only does about 20 or so more threat per proc, so this is still a choice that will give you much longevity as you can continue using it until you burn a vanadium/pearl or loot a master version of Storm Stance. Infuriating Tranquility is the highest of our standard single target taunts.
Level 54
Agitate Spirit- Taunt that interrupts and increases the hate of all enemies in an encounter towards the monk.
(Excellent choice for monks who tank. Took this one.) Dropping 800 threat on every mob in the encounter to open the the fight is a fantastic way to eastablish control.
With both of these choices for master 2s and the single target taunt at adept 3, I have found it is relatively easy to maintain aggro on multitarget encounters and have successfully held aggro on as much as 4 seperate multi-target encounters in emergency situations thanks to the high amount of threat generated by these skills.