As someone who only plays healer rarely on a whim, and never in serious endgame content, I really do agree with all of you. Tanks are too impervious (not looking at you, DRK, you're gonna die without outside healing in 20 seconds tops), and while DPS are considerably more squishy, WARs and PLDs are able to keep at least one up with them indefinitely. Good usage of Bloodbath/Second Wind also fills for the healers a lot.

So SE should either give healers something to do that isn't "keep up one dot, spam one GCD damage spell, oGCD heal someone who messed up or raidwides", or drastically increase how necessary healers are. Preferably both, so that you can still have downtime and do stuff with your rotation. Keep WHM as the simplest healer with one dot, Glares and the occasional Afflatus Misery, for people who like current healing style.