That said, this is an endgame spec, and requires really good gear. The concept for the build is to fully utilize Grave Injustice to max out on killspeed by resetting cooldown on Spirit Vessel
Plague of Toads (Explosive Toads): The spammable maindamage / aoe spell for the build. Originally for the build i used Toad Affinity... but with 1.04 and the (OP) mana regen changes makes highest damage frogs the best choice
Gargantua (Restless Giant): While killing trash this one doesn't do much, but it's not really needed either as your damage output will be so massive. However on championpacks the additional damage it does is just massive while providing tanking. It synergizes very well with rest of the spec where mainfocus is high damage in short amounth of time.
Grasp of the Dead (Death is Life): The choice for this rune is sort of a no-brainer. To spawn health globes Gruesome Feast... The additional zombie dogs it spawns just happens to be a really nice bonus without having to invest in the spell
Spirit Walk (Severance): I guess this is the part where i explain the playstyle of the spec, this is it's core... Spirit Walk should pretty much be used off it's cooldown, both for the purpose of dps but also to maximize downtime effiency, ideally it's beeing used to rush into a pack of mobs and on the way out.
Wall of Zombies (Dead Rush): High Burst aoe, i use this one pretty much of cooldown aswell as Grave Injustice keeps resetting it. This is the second opener after Soul Harvest (can of course be used first assuming Harvest buff is up)
Soul Harvest (Vengeful Spirit): In the way it works it's similiar to dead rush, while providing a huge dps boost aswell as some added survivability through the additional int(all res)
The obvious weakness of the spec is range, but i feel that adding Gargantua to it makes up for that, as championpacks can't be bursted the same way as trashmobs. I see the alternatives as Big Bad Voodoo and Fetish Army or Mass Confuse (Mass Hallucination or Paranoia). I think the other skills ties together really well, but this one comes down to preferance.
Gruesome Feast: Massive dps boost, mana regain (although not needed), indirect survivability boost through extra globes, well synergized with death is life
Grave Injustice: Self explainatory, added to it speed is king in a game like this. This build won't need all that much pickup range although i would suggest +20-30.
Spirit Vessel: -2 seconds on Spirit Walk, aswell as it's "cheat death" function
As i see it Spirit Vessel can be changed for Pierce the Veil, however this requires really good defensive gear which can be hard to obtain considering the importance of offensive stats.
First of all it's hard to say what works for someone is going to work for someone else, but ill try give some pointers.
I've testran this spec through all of A3 3 times with no problems. The stats i had on my testruns was 94k dps, 700-800 all res, 28k hp (it's gimp but im gearing for maxeffiency on my wiz atm and the defensive stats are secondary until now where i start investing in them),
For A3 70k+ dps is needed for A3 (high APS should be a part of it)
Would say 35k hp+, might need more in getting used to the spec
700 all res+ / armor ilvl63 base as minimum (the more the better is obvious for these stats)
The best way to get an idea of a spec is to test it out yourself, so im gonna leave it at that.
I think there are options to even push speed further with Grave Injustice and utilizing pickup range with Locust (Pestilence), but i haven't really tried to get into theorycrafting such a build yet however i think this is a really solid (+fun!) build that does the "trick" faster then any other WD build i've tried myself.