I have a 45 Operative and a 25 sniper. I personally play the operative differently than most after reading this. I started out in concealment spec till i saw an operative pull 300k using lethality and I have never gone back. As lethality spec I am always the top dps in wz's. I do over 300k dmg in almost every wz cept the 1 with turrents. I have manged to go through a few Hutta Balls games with 300k dmg and no deaths.
I am rarely in stealth mode personally, i am to busy running around throwing poison grenade and darts out on everyone. I keep my range unless i see a helpless person at which point i will get into melee range to hit them with a weakening blast and then cull. Lethality operative has enough ranged dps that they dont have to get in close unless they want to. That being said I am not killing 1 person at a time like a sniper is i am spreading my dmg out across everyone on the battle field.
I have played my operative as a healer and in a WZ the last thing i was looking at on people was cleansing debuffs mainly because they are so hard to see on a friendly target. So most of my poisons run there full course on a person unless they are a healer or agent and smart enough to cleanse themselves.
Side note Operatives are beast in the 2 none Hutta Ball WZ's. The power of posions to keep a person from activating a turrent or remove or set a bomb is so key in winning those 2 types of matches. You can throw a posion on everyone near a turrent and stealth and give your allies a good 10 seconds to show up and help out. Add to that the ability to snake a turrent from anyone in the game if they are solo guarding it. As mentioned before simple walk up hit them with a sleep dart. Start stealing turrent when they use CC breaker just stealth wait a few seconds for the debuff of CCing to wear off hit them with flash bang and steal the turrent. Or do it the other way around both ways work. I personally open with the sleep dart and finish with the flash bang because if they get a dot on me i cant cleanse the sleep dart is useless second as you cant get and stay in stealth mode.
My operative can kill almost anyone 1v1 warriors are the easiest with kiting and poisons. clip their tendon and just stay out of melee range keep posions up and shoot your gun.
As for my sniper. I have found that it required me to pretty much set up shop in 1 area and wait for enemies to come to me. They are great at keeping targets away from them and dishing out masive burst dmg from afar. But i've found snipers are less helpful to the group in all 3 of the wz's over an operative.
I give the operative the heads up over sniper for utility, versatility, and overall enjoyment to play. If you want to run around and kill people operatives give you the best of both worlds from being melee and ranged.