+FA dmg benefits your fetishes, it doesn’t matter if they are the Sycophants
Yeah, I actually did that earlier in the season too - I never really did the math, but it felt like the +15% PD was giving better benefit than two topazes. What I mostly meant when I said that your pants weren’t great though was that the +83% is too low. You should, optimally, have more than 95%.
Your CoE is really well-rolled, in a perfect world, you would want to have IAS instead of Area dmg but it’s still a really good one, and for a non-LoD build, it would be absolutely perfect. Given how much of a benefit you get from LoD for each ancient piece, however, you might be better off with even not that great of a ring that is ancient - if you can get one with CHC, CHD and socket, that should be enough.
Yeah, RG battles are the most difficult thing with this build. One mistake, and that’s it. With how slowly your Fetishes accumulate and with a lot of dmg mitigation coming from your Harvest, which is impossible to get full stacks of if the RG doesn’t have spawns, it’s really easy to get one-shot again and again. Perdition is particularly bad, but I did actually have this experience with Sand Shaper and his tornadoes too.
If you generally want to be a bit tankier, you can cube DoD and use Sacred Harvester instead for those extra 5 stacks of SH. You lose EF, but get quite a bit of extra toughness, which might actually mean more dmg output in the long run since you don’t have to dodge crap all the time, as you said. Socketing rubies also helps and, finally, Belt of Transcendence will make it easier to get your Fetishes up faster, even if losing Witching Hour does hurt.
In the end it’s up to you to see what works for you - experiment with the build and see what suits you. I hate playing glass cannon and fishing for rifts, so I take all the dmg mitigation I can, even if it means my DPS drops, but that’s just me.