well i have read the posts about it and got to say the only change needs to be to his movement speed(increase).
like stealthies in most games once seen its pretty much over and this game rings true also. i have played it a lot and can say that when i am trying to chase someone down after been seen it is almost impossible, considering for some unknown reason in this game when u back step you travel just as fast as when you are moving forward. so if you are having a hard time getting away from a phantom try shooting and running instead of just running.
at first i was getting a lot of kills but now it seems to be getting back to bout 1.2 - 2k/d in a match so not really much higher than normal so if your really seeing someone dominate it is probably hacking not the class being OP.
so that is my suggestion and a couple of ideas for those not playing him to counter w/o another special class/equips