I tried the build as a sentiment from quite a few seasons back and surprisingly enough it still works pretty well. I don't think it's possible to push high GRs with this, but it's nice for speedrunning low/medium ones and bounties. Not recommended for any runs where you intend to pick a lot of items, the whole point of the build is that you simply never have to stop.
I DO recommend putting Smoke Screen on auto-cast. It won't cast until you stop (and you have to stop for a split second every time you cast Rain of Vengeance) and you should be having it up often enough to keep Elusive Ring's effect on. You can also always cast it yourself when in need of some bonus movement speed - it will NOT disable the auto-cast. Just remember to turn it off before porting to town, it WILL disrupt your channel
The rest is pretty easy really. Keep your Vengeance up at all times (not recommended for auto-cast, here's why: ORotZ can only reduce the CD of ONE of your skills ON COOLDOWN for every hit. By recasting your Vengeance every time it's off CD you permanently have it on CD and thus increase the CD on your other skills. Trust me, you'll have it up before it ends ). Strafe around the battlefield, use Rain of Vengeance whenever it's up - preferably on elites and champions, or if there are none in sight - on some dense groups of mobs. Remember to dance around the monsters and avoid as much damage as you can and collect health globes for additional hatred from Reaper's Wraps. Cast Preparation when at ~1/3 discipline.
I am currently using Stempede for Rain of Vengeance, but if you find it hard to keep the enemy in place for all the beasts to hit feel free to switch to something that suits you more, like Anathema or Dark Cloud. Anything, but Shade. This rune sucks for this build.
OTHER BUILD POSSIBILITY:
There is a possibility of merging this build with 4 elements of Shadow's Mantle at the cost of Mantle of Channeling (replaced by Shadow's Burden), K'mar Tenclip (replaced by Natalya's Slayer) and Elusive Ring (replaced By Ring of Royal Grandeur), but I haven't tested if switching from Smoke Screen to "all-runed" Shadow Power is worth it, most likely not. It can be done though, hit me up if you tried it, I'm curious about it.
Anyway, enjoy the build and let me know what you think about it,