I played a Commando during beta and a Sage as well. The sage just got fairly boring, and personally I don't really see them as being that strong. If you want a healer that surpasses any situation I'd go Trooper. My aoe and single target are both amazing, add the heavy armor into the mix and its just ******.
However though I will say that you need to play with the mechanics to optimize healing output. I leveled from 1-50 as Combat Medic and didn't re-spec til a week after being 50. The sage I'm not so sure about...
Personally I got really bored with the Sage, my Scoundrel is more fun than the Sage.