5th Passive: weapon master
So in 2.4.3, some significant buffs were made to Wrath of the Wastes, specifically effecting WW damage. Putting this build into the realm of TXIII speed viable. However, to do so EFFICIENTLY(when I say efficiently, I mean spending no more than 2-3 seconds per elite pack), you'll probably need to be full ancient and a reasonable paragon. But right out of the gate, this is easily a TXI build with non-ancients and low paragon.
Legendary Gems: Using this build, gem choice is pretty free. The gems I recommend are based SOLELY on DPS calculations. This setup is THE highest DPS, hands down. You can make adjustments for more movement speed with Wrath or Hoarder.