DPS shadows/assassins hit just as hard. One big difference however is that the operative can be AOE'd out of stealth and denied a major source of burst whereas a shadow/assass can keep up those numbers regardless of stealth in a sustained manner.

Spam more Shadow Strike.

It's a matter of efficiency. You can either be semi-gimp, accumulate 0 upgrades through additional PvP and have moderate fun or bite the bullet, level to 50, and then finally have the chance to gain upgrades while doing your prefered MMO activity. Usually PvP is more enjoyable when you're geared enough to be useful to your team and not a burden. No matter how skilled you are, with decent gear you would be that much more useful to your allies. It would have been cool to at least be able to work towards that pre-50 but you can't with the unique 50 bag and comm cap.

I bought all the PvP lv 40 gear and still ended up with 1000/1000 commendations so I guess there's no reason to PvP till 50. It's like the game wants to punish you for trying to level up through PvP. How dare we not enjoy PvE travel grinds?!

Sounds like the stealth opener is what people are complaining about. Thing is that dependency on stealth to reach optimum burst is what makes it different from it's stealth brother- assassin/shadow which does excellent burst with no stealth dependency at all.

TBH getting 200-250k is very average for your decent low-level player focusing on DPS.