@Bagstone my math on area dmg was if both mobs 2 or 3 proc area dmg not just 1 mob to proc area dmg amongst them, but yes if only 1 mob does proc area dmg the dmg is not really noticeable but when u have like 5+ mobs clumped up and in some cases area dmg procs from all of them the amount of dmg you do goes in the low 100 billion dmg range
But that's the thing, you can't compare 15% sentry damage with an example of 100% area damage procs. In 9 of 10 cases only 1 (or no) mob procs area damage, so in 9 out of 10 cases sentry damage wins in your example, what's this going to show us? Area damage has a fixed 20% proc chance, you can't argue that "every mob procs it", ever. You need to do the proper math, otherwise you make wrong decisions.
Discussing Area Damage on shoulders is pretty retarded, tbh. Dex/CDR/AD/Sentry or Dex/RCR/AD/Sentry. Sorry to shut down discussion but why would you pick one or the other when you can have both?
I think it's pretty dumb to "shut down discussions". As soon as people do that you stop thinking and make wrong decisions. RCR/CDR can be translated into more DPS/utility - it's just super hard to do this. For example (just an example, not actual numbers!): You could argue that 8% more CDR means 8% faster Prep/Wolf cooldown and thus 8-10% more damage; 8% RCR mean 8% more hatred for CA before you need to regen, so also 8% more CA or whatever. Again - not actual numbers, just as an example. It's crazy difficult to do the math, so I don't know what the *actual, correct* numbers are. 20% area damage on shoulders means that every fifth mob will proc for about 10% of your damage (since half your damage, roughly, comes from pets). On huge packs (5+ mobs) area damage gives you probably more than that, but whenever you're fighting an elite pack, champions, or the RG, AD is a waste. So how do you compare those?
I think this discussion is very valid unless you provide the math why area damage is so much better. Note that I also said I'd go for both - area damage and sentry damage - but you didn't provide the answer what to drop then, RCR or CDR (let's assume non-0dog setup in which CDR becomes even more useful since Wolf/Prep are important sources of hatred). So, what is it? Let's discuss, provide math. But please don't make statements without providing any proof, it makes you look like a fool.
@dzajko: You're right when saying "some people don't listen or take into account the area dmg affix". I completely agree with you that people dismiss it too quickly. However, your math is a bit flawed. Area damage is better on shoulders *if you don't use enforcer gem*, and only for trash and packs of 5 mobs or more, but it's really really close (math below).
Area damage has a 20% chance to proc for the amount of area damage you have. In your example of 2 mobs, there are two times 20% chances that area damage procs for 70%. Let's look at an easier example of a group of 5 mobs: on average, one of them will proc area damage.
First of all, we need to check how damage is distributed among you and your pets. Let's assume a base hit of 100m just for simple math (it's low, but absolute numbers scale, we're just looking at percentages). So your sentries hit for 100m each, and you hit for 600m. Your sentries get either 15% bonus damage from sentry damage on chest, or 30% from chest and shoulders; in the first case that means sentry damage is 500*1.15=575m, in the second case it's 650m.
Setup 1: 20% area damage on shoulders instead of 15% sentry damage. You hit 5 mobs for 1175m damage, 575m of which are from pets so can't proc area damage. One of the mobs procs area damage (that's the average result, remember) and you get an additional 70% of your 600m hit as area damage, so the math: 5 mobs hit for 1175m, and 5 mobs hit for 600*0.7=420m from area damage, results in 7.975b damage.
Setup 2: 30% sentry damage (shoulders+chest), no area damage on shoulders (still 50% from paragon). You hit 5 mobs for 1250m damage, plus again one procs area damage, this time for only 300m. Overall damage: 7.75b.
So, in this setup area damage wins by 3%. However, area damage loses when...
... there are 3 or less mobs around
... you're using Enforcer (which is being used by many many GR60+ DHs)
... you're moving to pick up healthglobes and your sentries should rockets
... you're standing only 5 yards (!) closer to the mobs than your sentries (Zei stone)
And there are probably more reasons. I'm not a DH, I'm just interested in theorycrafting. So what's the TL;DR? Sentry damage vs. area damage? Imho, it's both. We haven't even talked about RCR and CDR. It all depends on the setup; if you've got a 0dog WD in your group it's easy though, you want to get rid of RCR. In other cases, it's a tough choice.
In my personal opinion, sentry damage wins - because of the gems. You're either using Bane of the Powerful, which means you want to kill every elite pack - which means less trash in the rift you're aiming for and therefore less area damage to proc. Or you're using Enforcer, in which case it's a no-brainer for sentry damage.
I think this discussion is very valid unless you provide the math why area damage is so much better. Note that I also said I'd go for both - area damage and sentry damage - but you didn't provide the answer what to drop then, RCR or CDR (let's assume non-0dog setup in which CDR becomes even more useful since Wolf/Prep are important sources of hatred). So, what is it? Let's discuss, provide math. But please don't make statements without providing any proof, it makes you look like a fool.
Area damage has a 20% chance to proc for the amount of area damage you have. In your example of 2 mobs, there are two times 20% chances that area damage procs for 70%. Let's look at an easier example of a group of 5 mobs: on average, one of them will proc area damage.
First of all, we need to check how damage is distributed among you and your pets. Let's assume a base hit of 100m just for simple math (it's low, but absolute numbers scale, we're just looking at percentages). So your sentries hit for 100m each, and you hit for 600m. Your sentries get either 15% bonus damage from sentry damage on chest, or 30% from chest and shoulders; in the first case that means sentry damage is 500*1.15=575m, in the second case it's 650m.
Setup 1: 20% area damage on shoulders instead of 15% sentry damage. You hit 5 mobs for 1175m damage, 575m of which are from pets so can't proc area damage. One of the mobs procs area damage (that's the average result, remember) and you get an additional 70% of your 600m hit as area damage, so the math: 5 mobs hit for 1175m, and 5 mobs hit for 600*0.7=420m from area damage, results in 7.975b damage.
Setup 2: 30% sentry damage (shoulders+chest), no area damage on shoulders (still 50% from paragon). You hit 5 mobs for 1250m damage, plus again one procs area damage, this time for only 300m. Overall damage: 7.75b.
So, in this setup area damage wins by 3%. However, area damage loses when...
In my personal opinion, sentry damage wins - because of the gems. You're either using Bane of the Powerful, which means you want to kill every elite pack - which means less trash in the rift you're aiming for and therefore less area damage to proc. Or you're using Enforcer, in which case it's a no-brainer for sentry damage.
And regarding IAS on weapon, he was talking about 0dog setup where you have unlimited hatred, in which case IAS is just amazing.