I have to agree with Vanguard being pathetic damage in pvp. The other day, I was trying to kill a scoundrel healer. It was pretty funny. He literally stood in place, doing nothing but diagnostic scan, the heal over time, and the emergency medpac, and I couldn't get him below 40-50%. I'm not the best around, but running the AP isn't all that hard to manage, and I was pretty well geared (before the first bolster fix, in half DG/half campaign). I wasn't getting crits, so that had something to do with it, but it comes down to the plasma cell nerf really screwed us. Plus, every class can now get 8k+ hits with ease, but Vanguards are lucky to get a 6k hib.
Numbers wise, I seem to have put up decent numbers if I use explosive surge in groups, but if i want to tab dot, I would play on my scoundrel or shadow.