I, like many others, have been using 7/7 divines for a long time. It is generally regarded as a trait you'll want plenty of as a healer or DPS, especially coupled with the thief stone (crit chance) or Ritual if you want pure healing. With the upcoming patch, other traits are looking more appealing. Specifically, I moved from divines to nirnhoned / reinforced in anticipation. I'm losing 5.77% critical chance to make this change (as I've been using thief), and gaining somewhere in the neighborhood of 2.4k physical and spell resistance, or roughly 3.6% damage mitigation.

Damage mitigation may seem like a weird choice as a healer, so I'll explain my logic. The first thing to understand is that a dead healer is useful to nobody. If I go down, the group stands a pretty solid chance of going down with me. To prevent deaths from silly mistakes or high, unavoidable damage hits, I always tried to shoot for somewhere between 20k and 21k health. This range kept me alive well enough with, I believe, around 9.5k physical resistance, leaving me with around 70% critical chance for spells.

In general, as a healer, I find reliability to far outweigh the "glass cannon" approach. Although huge critical heals are cool, I think consistently solid heals are a better choice. When you focus on critical healing and invest champion points into something like elfborn to make those crits more potent, you widen the gap between the values of standard and critical heals. I would much prefer to increase the base healing value than the critical healing value, as it directly correlates anyway. I know that may sound confusing, so I made some visual explanations for an example.

Let's assume your base heal is 2000, represented by the darker of the two greens. With the base 1.5 multiplier for crits, that makes the crit 3000.



So say you invested in 100 points of elfborn for a 25% bonus to critical healing. That increases the critical heal multiplier to 1.75 and results in 2000/3500. This leaves a larger gap between base and crit.



Now assume you instead invested those 100 points into blessed for a 25% boost to base healing. You retain a 1.5 crit multiplier, but your end result is 2500/3750. That's a higher base AND higher crit than the previous two situations.



Now you of course have to consider that elfborn benefits damage as well. I'm not saying to abandon it, but it is simply isn't as beneficial to healing as pure heal value is. Basically, I'm saying you should invest more into pure healing than critical healing. As such, the role of a crit is reduced in the build, and the benefit of 5.77% crit chance is reduced along with it.

So this is where that damage mitigation starts to make a bit more sense. Because of my increased mitigation, I was able to reduce my target health pool. This meant more attribute points to spend. After passives, I am getting (very) roughly 150 health and 150 magicka per point. So pretty much every point removed from health adds relatively equal amounts of magicka. I lowered my health pool but my ability to survive is still better than before and my heals are more potent because of the increased magicka.

So I gave up about 6% critical chance in exchange for being a bit tankier and having more potent heals through increased magicka and redistributed champion points. I no longer have the exact figures, but my overall healing over the course of 100 casts is within half a percent of what it used to be.

So after abandoning divines for mitigation, I can take more abuse and my heals are more consistently high, just with a few less crits. I think the end result is a more reliable healer. It also doesn't hurt that I'll be able to handle solo endeavors like VMA easier.

EDIT:

Something that didn't occur to me until I got around to really putting this to the test is that a smaller health pool with higher mitigation results in effectively making heals more powerful. The healing value is the same no matter how much health you have, so a smaller, tougher health pool means you'll be harder to kill.