65 druid on TLP server
Spent a lot of DKP on Orb of Clinging Death from PoTime raid which provides clicky magic dot, Swarming Death, 432 damage per tick, 9 ticks.
Also spent a lot of DKP on Enchanted Crystal of the Synarcana, nervously hoping it works on clicky magic dots.
Test:
1. Clicked the dot onto a mob without the augment equipped. Spell info says does between 432 and 438 damage per tick for this dot. Not sure where the 438 comes from since the dot did exactly 432 damage for 22 ticks (2 casts.)
2. Equipped the augment and then clicked the dot onto the same type mob, same level, etc. Damage averaged over another 22 ticks was 507 per tick, an increase of 17.4%. Yeah, I get that it's not 40% because the spell info says "1% to 40% so there is a RNG effect per tick. High damage was 591, a boost of 36.8%. Low was 440, which is about a 2% boost. Every tick was boosted by something.
No complaints here. The mana-free clicky for druid's best dot at 65 is godly and this damage enhancement is godly as well.
Also using gear with Timeburn effect, which extends dots by 20%. So I get 11 ticks instead of 9 ticks out of every click.
As any damage caster realizes, nothing beats mana-free damage. Except for extended enhanced mana-free damage! If you have a reasonable shot at acquiring this focus, obviously I strongly recommend it.