instead of creating a new thread...
I have been using the healing relic for forever on my sin but only recently noticed it gives you about ~1.5% of your total health back if it procs every 20s. However, a shielded (+absorbed) hit would reduce the damage taken by ~7-9% for 6s which means it mitigates more damage taken than the 1.5% self heal you would receive. Especially in nightmare content where you have a higher shield build anyway.
Soo... the question is.
why is the healing relic considered BiS still?
Because a absorb proc relic doesnt reduce the damage you take by 7-9% when it procs. When i do the math with dipstiks formulas i get a 2,65% reduce in damage taken (~from 70 to 72% migation) when it procs.
Therefore, a absorb proc relic gets on average better then the healing relic when you get more then ~6200 dps (unmigated) on average (based on dipstiks data).
Currently the average damage a tank takes in 8 man nim is about 4-4,5k unmigated dps, so on average the healing relic would still be better.
Also the values dipstik calculated with are from sv hm (which has a lot more m/r and f/t (shieldable) attacks then tfb nim), which would make the healing relic even better for tfb hm/nim.
But this conclusion would miss important points:
Sin tanks already have a lot of reactive self-healing and healing (HD stacks, dark charge, 5% healing buff...),so for them its generally better to have more damage migation. More simple: A dead tank can't heal himself.
The damage tanks face in nim is not always the same and especially when there's a lot of pressure on the tank (when there's more damage then the average 4-4,5k) the absorb proc relics are way better then the healing relic (on average). Most of the bosses (twh, op9, kephess, titan, Styrak...) put most of their time the pressure just on one tank, so this tank will get almost double the damage while he tanks the boss and almost no damage, when hes not tanking the boss.
You can then obviously argument to use the click relics, as they will provide the best migation for short periods of time when you face a lot damage (assuming you activate them correctly). But tanks are not getting huge amounts of damage in 30 sec Intervalls, so the click relic lacks continuity (in my opinion).
In the end, i would say it's unclear which second relic is bis (apart from the fortunate redoubt, which because of the static defense gain i would consider bis).
Each relic type (proc, click, healing) has advantages and disadvantages. I prefer the absorb proc relic as a second relic, because it gives more or less continuity in uptime (doesnt have 90 seconds without a single proc), and because its better for high damage phases then the healing relic, but there are many arguments for using a healing or a click relic aswell.