During this quest, there are mobs called Slateskin Troublemakers that are running around, dying by themselves by a debuff called On fire!
If you simply tag these mobs after they have gotten the debuff, they will die by themselves, aswell as you getting all the loot from them.
They do keep coming in waves, so theres almost no downtime.
This can be used to farm Skyshards, Motes of Harmony and lots of greens.
A guildmember of mine got 7 of his skyshards in about 5 hours of farming last weekend using this method.
Ranged With pets are best for this as the Slateskin Troublemakers have a stun, and having a pet eat the stuns helps speed.
Put Free for all loot on, have one guy loot the motes and the other loot skyshards greens and such.
The location waypoint is 38.95, 79.42
Hope you find this useful.