The older transmitters would sometimes go out of tune (especially when the room temperature changed a lot) and they would occupy huge amounts of bandwidth. That's pretty rare these days.
From my experience, there are almost no broadcasters who over modulate or operate over power. I say almost as I hear rumors that sometimes seem credible, but have yet to witness firsthand a purposely over-powered or over modulated station. The people I work for tend to demand that the meter stay as close to 105% as possible without exceeding the legal limit. Kinda like me and my 5mph over every speed limit policy.
Back to WCLS, they seem to have tweaked it a little more as of this past weekend. It's sucking up a little background noise up on some quiet tunes, but I actually enjoy a little bit of that on an oldies format. Except for the relatively low technical quality of the liner voice, the station sounds prtty good now. Thanks for spending the money Dave! This evaluation is based on Dick Bartley's Saturday Night show...that's all I listen to on WCLS and I am very thankful they carry it. If they are taking requests, hopefully they'll also pick up Bartley's 4 hour show that can air anytime over the weekend. If they suddenly pick that one up, it will remove all doubt that someone from WCLS reads this site...