It is a tough thing to balance because either spies are impactful or they are nerfed to irrelevance. Making spies more impactful also made them more infuriating if you are on the receiving end. I share ridjack's opinion that the old system "was simple, a bit boring, but impactful and, most importantly, it did its job". I never did get the need to overhaul the spy system so drastically in the first place.