So, here's the link to my Armory:
The basic idea is stun and tank. You have at least 59 Discipline with the gear that I use, potentially 70 (if you get 10 on cloak and roll 10 on Spite), but I've found 59 to be more than enough for the majority of occasions. You have only 2 Discipline skills, and in most battles only one (Frozen is the exception...and Fallen Maniacs) that you really need to worry about, and with 59 Discipline you can cast SP/Gloom 6 times in a row so long as you wait the full 5 seconds just off the standard 1 Disc/second. Since you have Nightstalker and you should theoretically have at least 55% CC, you'll be casting SP/Gloom effortlessly.
The combination I use at the beginning of most fights where I use Vault to get into the middle of large packs of mobs is SP->Fan of Knives->Spike Trap->Spam Grenades/Spike Trap/Gloom until everything is dead. This way, you get into the fight with SP enabled so you're not 1-shot, you stun almost everything with FoK and then plant the Spike Traps around you and then spam the hell out of Grenades. This works amazingly, but requires pretty decent timing. The stun on FoK only lasts 2 seconds so you really need to plant the traps right after you pop FoK. You have a little bit of breathing room though because Numbing Traps, which is awesome, reduces enemy damage by 20% on top of your 65% from Gloom for 3 seconds. Since the Spike Traps take 1.2 seconds to arm, they should go off before the 3 seconds of NT are up, and you should be spamming Grenades by then, or at least very soon. By this point SP might be getting close to wearing off so you can pop it again, and you're essentially reducing damage by 85% all the time, and dealing a lot of damage without much movement so once you make your grand entrance, it's pretty simple.
The only reason I placed Elemental Arrow/Lightning Bolts in there is to help with picking off single enemies and/or enemies that run around a lot (individual Soul Lashers for instance, or Quilbacks). It works really well with the build though because of the 1.5 second stun on critical hits, and with at least 55% CC with the speed of DW things should stay still for the most part. The A3 KW is annoying to deal with, but landing a few hits with EA and then a lucky FoK usually gives me enough time to plant a Spike Trap or two under/near the KW to do damage to him.
The gear I have isn't the best and could easily be upgraded, I just don't have the money for it right now. Ideally these are the stats you'd have:
For low MP these stats should work:
If you can't get AR on a piece, get Physical because you'll be standing around tanking hits and it helps deal with Reflect Damage for the most part. If you can, get Hatred regeneration on stuff so you can ensure continuous spamming of FoK/Spike Trap/EA. It's not a huge problem, but every once in a while I run out of Hatred and it's nice to have some available at all times to use EA in a pinch (ie: A Fallen Maniac is chasing after you...)
I think for higher MP the new Nats set would be better just because of the better guaranteed stats you're able to get from the pieces, but I'm not able to confirm this as I never had a legacy Nats set so I don't really know how to gauge the 2 Disc/second bit. For lower MP however, it might be better because you should be able to get the necessary resistances from the other pieces of gear (I'm able to easily run MP1 with 320 AR).
I think that is everything. If you have any questions, I'd be happy to answer them. I'm not a pro theorycrafter or anything, I just liked the idea of a legit tank DH and found this worked well and wanted to share. I haven't seen this particular build before (I stopped playing my DH a long time ago and focused on my other characters so I haven't really been in tune with the new DH builds, so forgive me if this is a well known build).
In any case, I hope you enjoy!