Long story short, it is undoubtedly an Area-of-Effect Chaos Damage-over-Time skill that stacks on enemies (max 20 stacks). This means it will gain from increases to cast speed.

So we have now 4 things that people need POE Currency to look at a check out scaling:

AoE
Chaos Damage
Cast Speed
DoT

The other issue that people have is often that we will likely be standing still during casting. This may effect the clear speed, but additionally creates a problem with survivability. In the current state of the action, manual dodging is quite important as there is often very large hits from the late game. To survive these you often look at large Effective-HP (or EHP). This is going to be very prominent if you are going to get the occasional issue manual dodging (stuck in casting animations, especially with Spell Echo).

To cope with this, we are going to very likely could do with Energy Shield (ES).

So how do we take care of clear speed? One approach may very well be to boost the AoE with the skill. At this stage I am not sure with the base AoE, so it will likely be hard to say simply how much is needed on the tree and/or gear. Another more abstract way of raising the clear speed might be to use Obliteration Wands or even the Occultist's Profane Bloom node. Abyssal Cry you may also have an idea, but would increase the complexity for your rotation.

Obliteration lacks synergy together with the skill, mainly because it primarily targets boosting and augmenting physical damage. It is usually great with Blade Vortex/Ethereal Knives, and used to become really good for any budget Kinetic Blast build. Still, it can come having a simple spell damage modifier, and is usually corrupted with Culling Strike (though, so can other things - and you also would lose the spell modifier). These wands tend being extremely cheap though, and dual-wielding them would result in a great deal of explosions on your own screen which could be visually appealing (and again, ideal for clearing trash mobs).

Profane Bloom would allow one to use whatever things you like as well as have that chance in an explosion. The issue pops up though when an enemy is Curse resistant (as PB will only focus on a Cursed enemy). Dual-wielding Obliterations would give that you greater proc chance.

Nothing is stopping you taking Profane Bloom AND using Obliteration wands though, so remember that.

For the sake of testing, which is likely what I will endeavor first: An Occultist using two Obliterate wands, one corrupted with Culling Strike.

Now, for top-tier damage you could well be going Low Life which has a Shavronne's Wrappings coupled with Pain Attunement. It would require minimal changing from the tree I will post and could possibly free up some points to get honest. Still, considering budget I will leave Shav's out with this, almost like anyone attempts is brave enough to look at this in a new league the price would possibly end nearly high.

So we are going to use Chaos Innoculation.

Now, to get perspective - This is typically what my Essence Drain tree appears to be. Now, for pure damage it might actually be fine (and I is going to be throwing Blight onto among my existing ED characters to discover how it scales with this particular tree).
However, we have now cast speed and AoE to contemplate. When you buy POE Orbs from MMOAH, you find out the process is very simple. On MMOAH you will find the best supplier who are guaranteed to send product fast against the best prices.