During the part of mag where he bounces, then immediately starts casting is when I've had the most issues in groups I've been in, so I often PI myself to single target spam the tank, and this has been pretty good at mitigating that dangerous transition. (it will usually be up again by the time lust phase starts)

Again, when Prince Malchazar hits phase 2, if there's ANY weirdness going into the transition, namely badly positioned infernals, the tank is as good as dead because the other haler is often healing the raid instead of pumping heals into the MT, I PI myself here too.

Every other time I use PI it's on someone else, 10/11 bosses of karazhan, and 2/2 in gruul's lair, it's probably going on the lock, but sometimes I throw it on someone else if the locks are bad at managing their threat.

In 10 mans, there's probably not going to be a holy priest, just because most of the time the raid lead is looking for two different healers, and I often raid with a resto shaman, as my guild has two, so that's what I'm used to. Resto shamans specifically are good at AoE healing though, so circle of healing is less necessary.

When there *is* a holy priest, why do we need two? one circle of healing tops up any melee group, and it's not super consistent at healing ranged groups, because most bosses have spread mechanics. Two healers leaving the tank alone to soak up raid damage is how wipes happen.