Yeah but a warlords mark ring is a 'must have' for almost any build. It's just way too good to not use unless your build can't make use of leech.
Edit: Soulrend looks like ass. Barely more damage than ED but you lose all the mobility ED lets you have in exchange for a tiny bit of ES leech unless the "spell damage leeched as energy shield" also applies to damage over time from spell damage in which case some interesting possibilities might become viable.
ES leech gem looks busted as hell but it was already obvious they have been quickly working their way back to ES being 100 times better than life so not surprising.
Why do you guys find that quiver to be good? Trigger a 3link bow skill 1 time per second and give up all the amazing stats you can get on quivers, plus corrupts (cause if you corrupt it then it's a 2link bow skill)? Seems like trash.
Soul rend: 560 hit damage plus 1944dot
Essence Drain: 541 hit damage plus 1503dot
These are pretty fucking different. The advantage ED has is the dot duration is much longer so you can fire it once then forget about it while it ticks down, and use contagion to spread it also, but if you want to do a boss fight for example, you'd be better off spamming Soul Rend, since Soul Rend does much higher damage per second as long as you keep casting. On top of that, for aoeing, Soul Rend pierces mobs so it applies the hit damage repeatedly to them, while doing the dot to everything and the shorter duration in this case won't matter as much since trash mobs will die in less than a second anyway, that said you'll probably have to run GMP on it so that should even out, besides the fact ED also requires Contagion, while Soul Rend works on its own(but again you'd probably be well served having a 4L ED to dump on bosses too).
Overall slightly different niches and playstyle. Can use both though and drop Contagion. 6L Soul Rend and 4L ED is probably going to be a fuckton better than 6L ED and 4L Contagion for both clear speed and bossing, as well as general QoL. ED Contagion will only be better on maps with really really high density where you kinda cast the spells once each and then just run as your contagion keeps spreading and killing stuff with ED's dot, but that doesn't happen that often(Breach areas for example are like that).
As for the quiver, triggering a full 3link has a bunch of uses. You can for example apply bleed so you can use bloodlust on your main skill(also get some free bleed damage out of it), use frost arrow for some free chilled ground everywhere kind of shit. Another nice utility setup would be Frenzy+Power Charge on Crit+Onslaught, which basically gives you all that shit for free while only using your main skill. It might not be the best damage option, but will be pretty neat for general mapping.