I know the Romulan Commanders are suppose to be tough, but I didn't expect them to be Ninjas. How are they going invisible and still dealing heavy damage to your toons that can only just stand there hoping to survive long enough the fire back. This strange power is both exploitive and abusive to our toons. OK, it is a challenge, in seeing how many abilities I have available to overcome what amounts to a one shot kill. Balance needed or give us some strength to our survival skills. Especially when I use a medium shield and get no shield recharge from it.

I think they're using smoke grenades.

Just run atop the "invisible" guy and pulsewave him. Its AoE, so you don't have to actually see your target.

canis36 got it I believe

The smoke grenades, sometimes you miss the effect. Often I haven't been able to see anything but 1 or 2 of my bridge officers seem convinced there is something in that empty field and are blasting away...then the corpses start dropping