I've been toying around with a blizzard farming build off and on for quite some time now so I am fortunate enough to have had gear to test with on the PTR.
Here are some items of interest
Here's a link to the video:
Here's a link to some footage of the build in action:
****MP5 Farming Footage Here*****
This build has gone live and I'm now able to farm MP5-7 with very little trouble. I'd definitely argue this is faster at farming Demonic Essence than Archon/CM builds.
I've made an adjustment
1. Teleport - Wormhole instead of hydra. This allows me to teleport around without having to kill white mobs and just kill elites while farming demonic essences
2. I've been swapping between Arcane Torrent and Arcane Orb for direct damage. I still find using Ray of Frost - Black Ice does more damage and allows you to create choke points very easily in Vault of the Assassin.