Add a short cooldown to the traitor invisability cloaker.

[I-Sett]

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.