I’ve been theorycrafting a build around Drain Life and I wanted to see what the Lock forums were saying about it, here’s how I see it:
Assumption: Level 60 test lock on the beta.
Drain Life deals 755 damage over 4.7 seconds, healing for 500% of damage done (3775).
Drain Soul for comparison deals 1415 damage in 4.7 seconds, so a bit less than double DPS. I know about the Necrolord Drain Soul discussion, but bear with me here.
Inevitable Demise (new talent) increases the damage of Drain Life by 12% per stack, stacking 50 times, up to 600% increased damage. So that’s 755 * 6 = 4530 damage, and 22650 healing. For comparison, my test lock has 23000 HP, so that’s a full heal.
If you pick Night Fae you get Soul Rot. Soul Rot deals 100% SP damage to 4 targets, and Drain Life hits all 4 targets while Soul Rot is active. So that’s 4530 * 4 = 18120 damage, and 90600 healing.
You will also likely need to take an Endurance Conduit in your covenant system, for which I recommend Accrued Vitality, which doesn’t seem properly implemented yet - but heals up to 100% (depending on Conduit rank) of damage as extra healing as a HOT over 10 seconds after it ends: so thats another 18120 HOT.
So what I’m saying is that while the Necrolord Drain Soul build seems pretty crazy for single target execute (like raid bosses), for M+ or world content, the Night Fae Drain Life build, assuming you have 4 available targets, is going to do like 3 times as much damage probably, while also making you functionally immortal for ~15 seconds of every minute.
Oh also, in PVP Affliction Faes take it to another level, because Rot & Decay (PVP talent) increases the duration of all your DOTs by 1 second whenever Drain Life deals damage - and with Night Fae its hitting 4 targets with every damage instance, and further Essence Drain (PVP talent) reduces damage taken by 25% from targets hit by your Drain Life, which again - now hits 4 targets instead of 1.
If I missed the discussion posted somewhere else, let me know, otherwise - Discuss! 