Thunder I feel like you already have an idea of where you want your version of this build to go, which I actively encourage you to follow up on. However, it's clear you either do not understand the function of the nodes in question or perhaps do not see past the obvious. I will say, that the interaction is elusive to someone unfamiliar.
First, "Egoism is useless": Golem has 4 attacks, maul slam, maul jump, rampage, and melee basic. All with different base physical damage values as well as independent damage scaling values. I won't go into the math behind how these damage values add up on a crit, but I'm sure you can assume a 40 base damage attack with a 200% increased scaler with 1200% increased physical damage with 275% multipliers would assure a very hard hit if a crit could be guaranteed. Now imagine this being done 40% faster (Blind Fury). Fair enough?
Lone Watcher MAY save from minion drain, but it also does some other things, like increase the duration by 100%. This is why we take the node; egoism adds a CD to dread shade, and the added CD is what makes the node balanced, without adding a CD, this skill would be busted. We alleviate some of that pain from the CD with LW.
Pernicious Pact is used here to ensure our golem dies a slow death. You may say, "Well that's dumb, why would I want to do that?" Clearly, this is where the understanding becomes lost, which is fine, and took me some time to really find the best way to use Flesh Harvest. However, I guess you could say "It's my job" to find this kind of functionality. Everlasting poison never expires. It's constantly chipping away adding unlimited stacks of poison, however, our golem does regen fairly quickly with Hunger and Bone Growth. This not only makes him tanky but also heals us pretty well. Without the golem dying slowly, we would never feel the effects of Flesh Harvest. Typically, by the second time we're casting Dread shade on the Golem, he should be about 60%-70% life. Ideally, we would like to see him in the 50% range. With 2 points in Flesh harvest, this would give around a 32% increased effect to ALL OF THE buffs from Dread shade to the minions AND you.
When it comes to questioning Dread Phalanx, again, the functionality seems to be lost to some. We may have lost skels, but we gained significant damage from them (80% MORE to be exact). Since you can clearly see we do not scale minion health or regen anywhere, they rely on the melee damage they do to leech health. Both in the skill trees AND our Ribbons of Blood ring. They leech a % of the damage they do, not a flat numeric amount. In this scenario, the harder the hit, the bigger the heal. So you could drop phalanx, and "add more bleed" but they would be mopped up in front of you and almost instantly decimated. In our case, it is better to have less, that hits SIGNIFICANTLY harder and has incredible self-sustain. Leaving us just having to spam Wraiths, and a 16-20 second cycle of dread shade and golem every minute or so.
I hope this pulls back the veil slightly and gives you a better insight into the build's functionality. If you have more questions or want to go over ideas with me (I commonly take in feedback from my chat), my Twitch channel is live at 10 pm central on a daily basis.
-Good luck-
EMP