Healing sucks. It’s why I don’t do it anymore. It use to just be in Mythic+. Now even the raid sucks to heal. Never seen so much NPC healing and gameplay dependent dispels in a raid before.
As a healer, the tank is usually the only one I have to do anything with on Rezan. Both my current M+ toons are night elves and I usually run with a nelf DH, too. Between the two of us, we can negate Rezan’s first two pursuits, no matter who he targets (fun fact for anyone who may not know - if Rezan targets your gnome/dwarf/human/whatever buddy, a night elf can shadowmeld and it will break Rezan’s pursuit, even if he’s not pursuing the nelf).
Things like totem boss disease and tott gauntlet disease where it’s going out on everyone; my thought is usually to Cleanse the healer or a dps with less defensive options (hunter, mage) and just leave em on myself because the extra tank dmg is usually nothing.
I’m not the highest rank healer in the world so others may have a better strat.
I typically dispel myself unless someone else is really low and in danger of dying. I feel if I’m alive I can take care of the rest. If I know I’ll be preemptively using a defensive I may dispel someone else.
For the totem boss in AD though sometimes I don’t even dispel and just do aoe heals to the whole group. Dispelling to clear one person (usually myself) vs just continuing aoe healing is a wash.
For the ToT gauntlet I’m cooldown rotating aoe heals the whole time during swell because most dps can’t help themselves from blowing all the little adds up. I save revival (mass dispel) for a really bad high stack as well. It’s a risk on using a global on a single dispel vs an aoe heal, but if I do I’ll normally dispel myself.
I never dispel the tank because like you said they sustain themselves. This is important on the trash after the first boss of Fall where a nasty debuff goes always ok the tank and 1 other person. Always want to dispel the non-tank because the tank can take care of themselves.
Edit - just realized you may have meant who you should dispel as the tank, in which I’d say normally the healer for sure. Let him handle the party.
Bolstering doesn’t increase HP anymore and the damage increase it does deal is on the mob for a very short amount of time (if you manage it correctly) and it doesn’t even affect bosses.
It’s a nothing affix. I would deal with it literally every week instead of fortified or tyrannical.