Now try the same in ranked warzones.
I play Merc Healer since the release. I was one of the best healer on my server before 1.2, I was OP. But finally it was okay. Until server merges and ranked warzones. I spend my evening dying again and again, with a guard or not, with a IA heal or not. Because there's so much burst teams (powertechs and snipers are the ****, and warriors are our anti-class, enjoy).
Maybe Merc is fine. But powertechs and snipers are not then.