Actually, turrets can shoot some pretty hard shots if you train them up. I thought they were useless but apparently that's because 9 out of 10 Federation Engineers put no points into them, so that by Admiral rank their turrets are just pathetic.
Once in a while, though, I run into someone whose turrets actually hurt. Still, the turrets are immobile and the other deployables still seem pretty worthless so I'm sticking by my story that deployables are a poor choice for PvP.
Anyway, I think Min/Maxers create KDF "Aliens". The advantage of the Alien is you can pick all of your traits rather than getting stuck with a couple canned ones. Like the Gorn has a physical strength trait which is pretty powerful but kind of silly since melee PvP is not that good. So you're kind of throwing away traits by picking Gorn. Klingons get a couple decent traits but I'd probably pick others if I went with Alien as my race.
Some good ground traits off the top of my head:
Stubborn -- hold/placate resist
Sure Footed(?) -- whatever trait gives you 50% root resist. Roots suck.
Peak Health -- +10% health. It's not awesome but it has definitely saved me.
You could get a +stealth one but I'm standing by my argument that stealth isn't that great, especially in these 5v5 deathmatches. If we had some objective maps, maybe stealth would be more useful -- sneak in, steal the enemy intel and then run for it. Oh wait, that's Team Fortress 2, a game with far superior game modes compared to STO.
+Perception might be good. Again, stealthers aren't exactly a big problem but I hate letting them use it as an escape method. I want my kill point!
There's at least one ability (Luck?) that claims to increase your expose chance but it doesn't say by how much.
As for class, I think they're all good. I think if you want to be the most independent, you'd probably want to go with Science. Their wealth of holds and so forth will give you good odds of getting exposes, or escaping when you want to. Engineer probably a close second, since Weapons Malfunction is such a pain. I'm Tactical and enjoy it greatly and I'm always the top damage dealer (and I dare say, top killer) but I need a team with me to live up to my full potential.