Mending relics are only optimal for Shadow/Sin tanks.
They're quite terrible for healers. Stick with the Dread Guard and EWH Boundless Ages relics.
As a followup to the question I asked above, I'm trying figure out the why on this and I can only guess that it's the mechanics of it, but if someone could confirm this for me I'd appreciate it...
So the heal proc relics are bad for healers because they can proc on anyone they have a healing effect on, so the proc may go off on someone who doesn't need it then be down when it would be useful for the tank. And as such because the Shadow/Assassin heal is for themselves only as it procs off combat stance then when the relic procs it will only proc the heal on them, hence why it's such a large survivability upgrade for them. Is that correct or am I misunderstanding the mechanics of how the heal is assigned off that relic?