A Henshin has about 30 more PRR and 10 more dodge than the average Monk, and there are Rogue splits that can give you even higher dodge with temporary 100% dodge clicks. Stick builds are the dodge kings, and between the higher defenses, Cauldron, and cleaves, are more passively adept at handling mob groups. The key term there, though, is "passively". A Shintao Monk has Dire Charge (or should), Stunning Fist, and Jade strikes - on Henshin where a spawn of Crowns/Reapers can mean death, a Shintao can control it. Pretty much Stunning Fist and Dire Charge should always be used on CD unless they're stun immune, in which your Tomb of Jade would be used (such as Reapers or crowned undead). Jade Strike and Smite should also be used on CD as they can be free CC and are extra DPS, though I'll use those specifically on Reapers if Tomb is on CD.
One thing that can help you is if you establish combos and attack priorities. For example an already tightly set group of mobs you'll want to enter with a Dire Charge > Helicopter Kick (WWA) > Stunning Fist/Tomb most dangerous mob... a spread out one you would Abundant Step in > Stunning Fist/Tomb most dangerous mob > (and assuming mobs have come in on you so they're closer together) Dire Charge > Helicopter Kick... and those are just intro combos. They can be made more complex with weapon swaps (such as to get 1k HP trigger before swapping back to Duality), and how you'll handle mobs in priority down the line. You may be more single-target focused, but that Helicopter Kick hits hard, and often by the time I'm done using my single target DPS to kill priority targets, the rest died to the spins.
Though you're comment of trash dying too fast to get to use your Action Boosts... LD is built around the use of Action Boosts -- not only are you getting 100mp with Prowess (the 100mp is a remnant of the original coding. I expect it to be nerfed/fixed to the 75 stated), you are getting +1[W] and 50% helpless. You should be using ABs on those trash fights, and if you reach a Shrine with leftover Action Boosts and had a fight where you did not use one, you're doing it wrong. I load both 30MP and Haste boosts from LD. If you know that the gap between shrines will be longer, you can interject Unmovable and Thick Skinned into the AB rotation. Like a caster uses shrines to get their blue bar back, you use it to get your action boosts (and clickies if you use them) back. As long as you properly rotate boosts, you have 10+ minutes of continuous boosting with a few Unmovable/Thick left at your fingertips. That is before considering gaps between fights and any AB recovery you could do with a TF weapon (a TF weapon for Vuln stacking and AB recovery is a good thing to have in your pocket). I usually last 15-20 minutes easily before running out of boosts, and rarely need to even consider using the free defensive boosts from LD as shrines usually are close enough together to be fine with just MP/Haste usage.