The reason on Cho'Gall is because it is easy farm content for us and our other healer's don't need the innervates so I just have fun and bubble spam as much as I can. On most of our farm content like that I do that just, like I said, to piss off the other healers so they get bored.
In regards to the WoL all the deaths except that of Lore and Rick were poison bombs (Lore's was still the direct result of a bomb), not much we can do there even with PWS with the dmg you take from the cloud it won't absorb enough to protect you for that. In the case of rick i believe i was OOR which is why I didn't hit up PWS (he had heroic leaped away and got OOR of all of us if i remember correctly). In the case of Lore he was hit by the bomb as well and just dipped very low and the cloud got him.
Of course I do agree with you 100% about the effective healing but the reason I still do it is because I have those innervates/tides/CDs. If I didn't I would prio my bubbles (I already prio them but I can afford to do even more then I need). For example; I would prio tanks/healers, people with raid debuffs (I.E. Flamethrower) then people who have trouble with some mechanics that cause them to take avoidable damage.