My experience of being a sage healer is, it sucks in Pugs were no one helps or communicates but if you have a few friends, and use a voicechat program, it rocks.
Sage healing has big holes in it, holes that can be plugged with a tank/dps friend. You keep them alive, they kill anyone who even looks at you funny.
Still, once you get a reputation as a good healer, expect to get focussed...a lot. I plan for this and make them work hard to take me out, which means in effect I'm still helping my team in a way.
get used to dying, not getting thanks or many medals and have melee smash the force out of you.