Honestly the biggest issue is the cap is low, DD reach it quickly, and then have no way to get rid of it.

Lowering enmity from damage will only delay the same outcome. Eventually you will get to a point where everyone is capped, and then we are at the same place as before.

We either need a way for tanks to absorb enmity from the party
Enmity from damage to be insanely low
Or more dd need a way to constantly douse their enmity,

Thf have trick attack (have it transfer % of current enmity as well)
rng has decoy shot (decrease reuse 3 min so it can be kept up and make current enmity decay faster)
drk - Add a huge -enmity affect to dread spikes
mnk - Give monks feign death (plays dead for 1-2 seconds and drops x % of enmity, 60s reuse)
drg has high jump (drops 50% enmity every 120 seconds-> lower to 30s reuse)
Pup can ventriloquy

The abilities are there, they just need to be tweaked to make more sense in modern combat. Pup is the only that can really control their hate 100%. And most people wont even bring one and their combined dmg with master + pet is > mnk. Honestly the only DD that shouldn't be able to lower their enmity is SAM, if they are gonna be king of dd they should have no way to lower their enmity.