2. Physical Skills Deal X% more Damage

The EP explosion scales with the Physical element stat. This means if you can't find a Fist of Az, Doombringer is a fairly good offhand option.
Other good sources for this stat are Bracers (20%) Ammy (20%) Andarial's Visage (20%) Stone of Jordan (20%).
3. Monsters Take X% More Damage

The stat that makes monsters take X% more damage will increase the damage they take from Exploding Palm explosions. Strongarm is easily the best source of this as you will always be using Cyclone Strike to group monsters and CS activates Strongarm.
Additional good sources of this stat are Mantra of Conviction (10%/20%) Inner Sanc - Forbidden Palace (30%) EP-Flesh is Weak (20%) Crippling Wave - Breaking Wave (10%)
4. X% Bonus Damage to Elites

This stat only scales EP's damage when the explosion hits Elites but it is a very important stat none-the-less because trash monsters have such low HP relative to elites that you NEED this bonus to make trash-based-EP's actually kill elites and their adds.
The main source of this stat is 2x Diamonds in weapons (20% each) and SoJ (30%) or Unity for 2x Unity eHP (15%) Aughild's 2x +RORG (15%) Blackthorn's 2x + RORG (10%)
5. Area Damage
The explosion from EP can proc Area Damage which means it scales VERY well with AD.
For example, if you have just the 50% AD from the paragon utility tree and you are fighting 6 monsters, when the first shatter-EP explodes, it hits the other 5 monsters, each one has a 20% chance to proc AD which means that EP procs, on average, one AD.
The AD hits 4 of the remaining 5 mobs for 50% of the damage of the EP explosion. This means it deals 50% damage to 4 of the 5 targets for a total damage multiplier of 0.5*0.8 = 0.4 or 40% more damage.
The more monsters you are fighting at once, the stronger AD becomes.
Given ideal circumstances, AD might be able to hit 10 monsters. This will cause it to proc twice hitting 8 of the 10 monsters twice and the other two once each for a total of two hits on 9 of 10 monsters. Given 50% AD, you just increased your total damage by 0.5 * 2 * 0.9 = 90%!
So....
In the end, your EP which starts at 50% monster health gets multiplied by each of these stats and can end up at pretty high levels.
My monk, for example, has a 97% FoA, 40% phys, 59% monsters take more, 75% elite, 68% AD.
This results in 0.97 (FoA) * 1.4 (phys) * 1.59 (MTM) * 1.75 = 3.78.
My EP's hit for 378% of the monster's health vs elites and 216% of the monster's health vs all other targets.
Assuming I am fighting 5 monsters, AD takes that up to 3.78*1.54 = 5.82 or 582%
Elites have less than 582% of the HP of their adds (usually) which means a single EP on an elite add will likely kill all the other adds AND the elite.
ConclusionCyclone Strike monsters together, Place Exploding Palm on a couple of them, freeze them with Frosties/WoL-NL, shatter them with Rimeheart+WotHF-FoF, BOOM.
Using this spec, I am able to clear T6 "efficiently" IE: faster than other monk specs, slower than some of the other class' specs.
Thanks for taking the time to read all this!
As always, if you have any questions, leave them here and I will do my very best to answer.
