Let me preface this saying I rarely PvP, and even more rarely enjoy it. I've enjoyed PvP (in BGs) on a frost DK (specced for it), and occasionally on my Rogue (not specced for it). But my experience is limited. My performance as the DK was actually better than most of the other players in random BGs, take what you will from that.
The other day I was on my new (second) druid, level 79. Decided I'd just do a few BGs to get to 80, first time really doing any PvP on that toon. As Balance, I just got my ass handed to me on a silver platter. No matter how I tried to approach people, even though I was in cata greens, I just could rarely kill anyone and even more rarely stay alive.
After a couple BGs I switched to resto and actually felt like I was useful. Even occupying the time of 3-4 opposing players just keeping myself alive (and others) for staggering long amounts of time.
So my question is just this: is balance a terrible PvP spec, or did I just play it horribly wrong?