Add a short cooldown to the traitor invisability cloaker.

[Paineframe]

I seem to recall there being a security-spawning set of thermals a while back, when thermals made you a nigh-omniscient securigod (slight exaggeration perhaps). Why not just bring back this extra set, introduce a few more cloak counters (flashes) as others have suggested and call it a day? It's far preferable to have a cat-and-mouse game than make everything out of soft foam-rubber, in my opinion.
In summary: Powerful Items need powerful counters, not simply to be made less powerful.

No, the whole "counter" concept is unfun, because then either you have the counter and the original item is harmless to you, or you don't have the counter and you're helpless to resist an enemy that picks you apart with impunity. Back in the days of cloak rampages, you were totally helpless if you weren't one of the two people on the station with thermals, so the only things you could do were hide away in a locker or one-tile-wide hallway and huddle there in fear clutching a flash until the detective or HoS caught the cloaker - assuming, of course, that either of them was still alive.