Engineer is my favorite third tier perk so far. Pair that with UAV, Hunter drone, and CP with the PDA and its worth it.
The problem with black hat is that tips me off that you're in the area where my bouncing betty is so I'm ready to take you. I might have otherwise been oblivious or didn't hear you trigger my claymore or betty.
I got a little highlight reel that shows the liability of hacking gear, especially when it's on the point you're trying to cap.
But cold blooded is a hard counter to the traget finder.
Just hit them with a Sticky grenade (Semtex). Seriously shouldn't be that complicated. Either that or just avoid them, no point in getting yourself killed going after the same guy countless times, it simply leads to more frustration and makes advancing yourself that much harder. Honestly, I don't even think it's that good, in my opinion this game is very balanced.