The Spell Drain Life is seriously underperforming, such that is almost better to not even use it it in favor of running away or using bandages instead. This particularly bad because it seriously impairs the Warlock classes’ durability and disrupts 1 of the chief class fantasies of a playing a Warlock: The fantasy of being a ruthless spellcaster that steals strength from their enemies to fuel their own life. I don’t pretend to know why Drain Life has been so heavily nerfed, but how it was nerfed is probably the worst way because it has completely broken the spell’s usage in any capacity; it does very little damage, does very little healing, and the mana cost does not justify the effect.
In my opinion, Drain Life should be comparable to the damage output of your basic filler spell, Shadowbolt; I don’t count Incinerate because it replaces Shadowbolt and gets a lot of damage buffs via mastery. The damage calculation of Drain Life should be based on purely the baseline damage output of Shadowbolt, before talents, and before stuff like mastery. The reason Drain Life needs to be comparable to your main filler in damage output is so the player only ask 1 question: do I need healing or do I need more dps potential? Warlocks should not have to sacrifice their dps output just to try to stay alive. Especially when you compare other classes’ healing effects like Healing Surge and Flash of Light, which have shorter casts, can be cast on others, and Heal for more.
To get usable numbers, I tested my own Warlock at level 80 Affliction, in patch 11.0.5, with no Shadowbolt- buffing talents (CkQAA81jxQD71lYhS/t8p6HgAYxMDYMTzMLjZbmZbmHYmxsAAAAmhZsNzMDzMzsMDzMAgxsssMGGzmZaMzMskZLDLGAAAAAAAAYY2GA), stripped naked to test baseline damage output of Shadowbolt.
Base Stats:
18,604 Int
86,454 Stam (1,633,980 HP)
2,500,000 mana
5% crit
20% Mastery
Tested on Damage Training Dummy in SW.
Using recount addon:
10 casts of Shadowbolt = 19,810 - 20560 (avg 20154)
10 casts of Drain life = per tick (9 ticks) 2846 - 2847 (avg 2846 x 9 = 25,614 per cast) / Healing (1 channel) 14230 - 28465 per tick (avg 19926 x 9 = 179,334 healing or about 10% of your hp)
So interestingly, with base stats 1 Drain Life hits for 1 Shadowbolt, but I would argue that is still too low because you cast 2.25 Shadowbolts per channel of Drain Life (4.5s / 2s = 2.25) Or to put it another way, Drain Life’s damage output should be equal to 225% of Shadowbolt’s base damage. With that thought in mind, the actual average damage of Drain Life should be, based on the calculations above, about 45,346.5 damage over 4.5 seconds (5,038.5 per tick) with a total healing of 226,732.5 (25,192.5 per tick) or about 13% of your total hp.
But 13% even enough? I’d argue no. While Drain Life does not need to be as strong as it was when Life Tap was apart of Warlock gameplay, it should function as a regular source of healing comparable to a Paladin’s Flash of Light or Shaman’s Healing Surge. Personally, I think Drain Life should heal for 25-30% of your total health for every channel. The reasons for this are twofold: reason #1 Warlocks are immobile and frequently find themselves under fire from multiple sources (very much PvP in this case, but also certain abilities like Dark Pact or Health Funnel) and thus need a regular source of sustain, reason #2 Warlock damage for the most is dealt over a long period of time (unless you’re playing Destruction) and therefore, Warlocks need more time to get the proverbial job done.
If Drain Life needs to be balanced, the last thing you should nerf is the damage. Nerfing Healing, or Mana Cost, or even Channel Time are valid methods that will not negatively impact, in a big way, the regular use of such an ability.