You make good points, but with overhealing giving lots of Hate, it really puts some pressure on other classes..which I think is good. Everyone needs to be over the bar or else it all fails. If the tank taking too much damage, the healer will have to heal more, and take aggro, while you're trying to get the healer in the clear the DPS start to pull. Binary mechanics are never great for a game, and tank and spanks can be a snooze fest sometimes. I think the system they have now does a pretty good job at what it's trying to do

EDIT: Whoops, this was in reply to Maelwys's post