Signet of Vampirism is bad. Most of the necro community knows this, but I haven’t yet seen a total breakdown on why. It’s known that the ICD on both passive and active (especially the active) kills it from being useful as a heal, but here are a few numbers to consider.
First, a link to a build showing the highest possible Healing Power for a necro to obtain. Not listed are the friendly Warrior and Guardian, running Strength in Numbers (Guardian) and Empower Allies, Banner of Defense, Banner of Strength, and Banner of Tactics (Warrior) as well as supplying the necro with extra Might. Also not listed are the maximum stacks of Applied Strength and Applied Fortitude from WvW. I manually factored in these boosts (other than the Might).
http://gw2skills.net/editor/?fRAQFAWCN2moZokNAMNgrIB-T1RDABGqEEq9DuU9nsU+BwDAQPdAqsgQAgDg3fPAc8xHf8xH3xHf8xHfcpAcaMA-w
The maximum healing power that a necro can obtain outside of unique PvE buffs is 2513.16. This will be relevant later.
As a self-heal, Signet of Vampirism is pretty bad. The passive effect is flat damage reduction, rather than actual healing, and its effectiveness gets reduced by poison The only time this isn’t the case is against Mesmer clones, which don’t ever hit for noticeable direct damage.
The active seems slightly better, assuming you can claim all five stacks you are allotted. This requires having Locust Swarm or a well running and hitting your target as you activate Signet of Vampirism, due to the long aftercast. Otherwise, you can only claim 4 stacks yourself.
These next comparisons assume 0 healing power.
Without claiming any stacks of the signet’s active, the base heal is 3960 at level 80. For comparison, let’s look at Consume Conditions, which has a base heal of 5240 at level 80. Given the 1.25 second cast time for both skills and their recharge, we get a base healing/second value of 109.24 from Signet of Vampirism and 199.62 from Consume Conditions. If traited for faster recharge, Signet of Vampirism goes up to 135.38.
Claiming all five stacks of the active heals for a maximum of 5920, just 680 more than Consume Conditions’ base heal. In addition, getting all five stacks requires using a second skill with a minimum of a 24 second cooldown (Locust Swarm traited with banshee’s Wail). At max potential, this is a 167.94 healing/second heal. Still lower than Consume Condition’s base HP/Sec. Traited for cooldown, this finally surpasses it with 202.39 HP/sec.
Now, how does Healing Power factor into this? Well, Signet of Vampirism scales at .5 Healing Power base and .2 per stack. Consume Conditions scales at 1.0 base and .1 per condition consumed. Assuming max stacks used on the signet, and equal healing power, we get the following thresholds for Healing Power in order for Signet of Vampirism to equal Consume Conditions:
0 conditions consumed: Signet of Vampirism always heals more
1 condition consumed: 110 healing power
2 conditions removed: 2560 healing power
I’m going to stop right there. Remember what I said the absolute highest healing power a necro could get was? 2513.16 As we can see, it is literally impossible for Signet of Vampirism to out-heal Consume Conditions with just two conditions removed.
Okay, so as a self-heal, it’s out of the question. What about group heal? Honestly, still not helpful. The base value for ally heal is 1960, assuming that ally claims 5 stacks. This is blown out of the water by the trait Transfusion, which incidentally also uses a skill that does more damage and AoE. The base heal on Transfusion is 2808 and does not require your allies to hit the specified target. The scaling is also much, much higher (1.8 total as opposed to 1.0). Then there is Well of Blood, which even manages to make Transfusion look small by comparison. Only 1672 base heal for allies, but scaling at an astounding 4.4 healing power total. If you want group healing, go with either of them. Even Renewing Blast can do much better.
Well, it has one more thing to look at: the damage component. It is indeed the highest damaging healing skill in the game, assuming all stacks get claimed. However, you would do just as much damage in most builds by just attacking instead of using the signet. For the same cast time, you could instead run Blood Fiend (and have similar sustained healing) and fire off a single Life Blast, which has a higher expected damage against everything but crit-immune targets (which the Signet can’t be used on anyway, save Stone Heart eles).
This skill needs considerable help. My personal suggestion would be to remove the ICD on the active, and then re-evaluate from there. I also suggest that the passive either lose its own ICD (as it still won’t heal the necro from anything but mesmer clone hits) or become a siphon with a unique ICD per attacker.
(edited by Drarnor Kunoram.5180)