Paul, you beat me to it. I do want to correct some factual inaccuracies in this thread, too.
Vindictive, you should take a look at Paul's pet damage thread, which can be found here:http://us.battle.net/d3/en/forum/topic/13349475072?page=1#2
It provides video proof for most of the assertions I'm about to make, though I'll try to link primary sources when I can. Let me preface the below by saying that I appreciate your effort in making such a lengthy post. Finally, you can also reference the Carnpendium for a thorough breakdown of all the build mechanics. We'd love to have a dedicated player like you add his thoughts:http://us.battle.net/d3/en/forum/topic/14527433038#1
Fetishes summoned by Fetish Army take bonuses from all % extra damage types.
This isn't technically the case. In melee mode, the FA get the benefit of whichever element their rune indicates. For LoD, this is physical, but for HH it would be poison and for TT it would be fire. As you note, when darting they take poison. Also note that this is regardless of the FA rune.
4. The Poison Dart damage boost DOES boost the damage of your fetish's darts Unfortunately because this skill deals low amounts of damage and relies on a lot of shooting fetishes, the difference in damage is not that significant unless boosted drastically.
I'm sorry, but this is incorrect. Damage dealt by fetish darts is comparable to that dealt by melee hits when you factor in typical gear, regardless of whether you're using CoE. Fetish darts can be buffed by the same effects that melee hits can (Z6, CoE, etc.), so it's not any more or less powerful. The lower tooltip dart damage is compensated for by the ability to buff the darts with Poison Dart damage.
Furthermore, the Poison Dart damage multiplier is a standalone multiplier in the damage formula, which means that 50% PD bonus on gear is a flat 50% damage increase from darts. This makes it very powerful. Here's the damage formula from Paul's thread:
07/05/2014 06:10 PMThis is the formula for Sycophant-Dart or FA-Dart damage:
Posted by PaulNg
[ Weapon Damage ] x [ 1 + (Intel/100) ] x [ APS ] x [ Fetish Tooltip ] x [ Pet Buff + %Element ] x [ %FA ] x [ %PD + SS gem ] x [ % Elite ] x [ Character Buff + Monster Debuff ] x [ Bane Trapped ] x [ Zei's Stone ] x [ CoE or F&R ] x [ Zuni6 ]
5. When shooting darts, Poison % extra damage has an affect on both Fetish Army and Sycophant fetishes. This is subject to SUMMONING CONSTRAINTS on Sycophant fetishes as outlined in the 2.2 patch notes.
The first sentence is totally correct. The second is not. FS have always done poison damage when firing darts, and the change in 2.2.0 has no effect on their dart damage. You can have 120% fire damage on gear and the FS darts will still benefit from poison bonuses.
My Fetish Army will deal ridiculous amounts of damage because of the 55% Fetish Army Boost, the 18% Physical Boost and the 200% Physical Boost from the ring, for a total of 273% bonus damage.
This isn't how damage multipliers work - they aren't just flat added. I noticed this reasoning in several places in your post. Different buffs (FA damage, elemental damage, Z6, CoE, etc.) are separated into groups and then multiplied together. Please review Paul's thread and the damage formula above for a full explanation.
Finally, I understand your strategy for letting the fetishes melee when the physical CoE cycle rolls around, but this isn't the way to achieve the highest DPS outcome. You're better served by putting all your resources into poison and Poison Dart buffs and darting all the time regardless of the ring's element. This is a more complicated idea to pick apart.
Here's what it boils down to: in your case (2) when you choose to allocate an elemental roll to physical instead of more poison, your FS (2/3 of your fetishes) lose the benefit of that damage entirely, since they'll spawn poison (from the 2.2 patch) and always dart poison, too. Your FA:LoD get 20% stronger, but only when they're meleeing, which is 25% of the time (4sec CoE cycle). So 33% of your fetishes do 20% more damage 25% of the time. This is a minuscule 8% damage increase to your total 23-fetish output, and only 1/4 of the time. The other 3/4 of the time (when darting), all 23 are about 14% weaker, since you don't have that 20% poison you gave up for the physical (1.2/1.4 = 85.7%). So the change to physical is 8% more damage 25% of the time and 14% less damage 3/4 of the time. This totals out to a net damage output of 91.5% over the whole window for all your darts. So by making that trade you lose 8.5% of your damage. This is entirely without CoE considered.
Now, for CoE. As you say, the physical cycle only buffs the 8 FA in melee mode. When you let them melee during the physical cycle, that 1/3 does triple damage, while the 2/3 that are FS do much less damage than they would if they were darting, since they no longer get the benefit of your PD bonuses. If you have 85% PD on gear your FS lose about 25% of their DPS output when meleeing, even with the higher tooltip damage for melee hits. This cuts into the buff you're getting from CoE.
Furthermore, melee fetishes attack more slowly than dart fetishes, which dart every time you do. A typical Carndoc will have at least 2.0 APS, while melee fetishes without T&T default to a rate of 1.25 APS. Again, refer to Paul's thread above.
So when meleeing with CoE physical active and your 20/20 elemental split, you get (0.33)*(1.8)*(3.0)*(1.2)*(1.25)+(0.67)*(1.3)*(0.75)*(1.2)*(1.25) = 3.64 times a hypothetical base damage of 1.
When darting during the physical CoE active with 40% poison on gear you get (1)*(1.3)*(1.4)*(2.0) = 3.60 times your base of 1.
This means that going melee during the physical window does just under 1% more damage than specializing your gear and just continuing to dart. So your CoE buff vanished due to split elemental damage, lower FS damage due to lack of PD benefit, and much slower melee attack speed. And that 1% more damage is only 1/4 of the time. And this is assuming that all of your FA land hits for the duration, which they might not. And
it ignores the time lost to them running into melee range.
Finally - and here's the kicker - melee hits don't pierce.
This means that your strategy does a fraction of the damage that your piercing darts would against multiple targets, and even against a single target the damage increase is insignificant.