There will never be stress-free healing

Zelmaru of Murloc Parliament and Ionomonkey of Screaming Monkeys are having an interesting public argument about the number of healers in a 10-man World of Warcraft raid. Their guild apparently ran into a situation where the standard 3 healers in the raid had the healing task well under control, but the 5 damage dealers weren't able to kill the boss before the enrage timer struck. Thus the damage dealers want to remove 1 healer and take 1 dps character more, while the healers feel as if that would punish them for doing their job well, and that the damage dealers should just man up and Learn2Play.

It is easy to understand the point of both sides. But regardless which game we talk about, or which raid size, as long as there is the holy trinity of tank, healer, and damage dealer, the general raid strategy will always be to *minimize* the number of tanks and healers. It is an inherent flaw of the system that any excess of healing or aggro management is a waste, but any excess of damage serves to speed up the fight. If you had a raid team which was perfectly able to take down a boss and the game would allow you to take one more person on the raid, you would always chose a damage dealer. There is such a thing as "enough" tanking and healing, but there is never enough damage output.

Not only is additional damage more useful, your guild is also more likely to have excess damage dealers than having excess tanks or healers. The consequence is that whenever healing is going well enough to offer the healers a relatively stress-free raid night, the guild is likely to remove one of those healers to squeeze more damage dealers in. In the end even the easy "fun" raids end up being as much hard work for the healers as the progression raids. No wonder healers burn out so fast.