Well, as Mike mentioned, if "You're thinking I'm Arby's" wasn't enough, I've got a source inside the "Mothership" that said there was a bunch of stuff- missing reports, having her cell phone ring during a RECORDED report, etc.
My guess is that with the D&M show doing so well in AM Drive (they were #1 M25-54 with a TEN share last book, and they're top 3 IIRC P25-54) that the bosses lost patience with subpar performance and pressured Traffic Pulse to get them someone different.
Add in that I've heard her on i93, and Barb's KVIL background may have played a part. If you want to be a teen/20's station do you want someone who was on the cougar's radio station...