IMO they should change their moniker because the "Mix" slogan is associated with hot AC.
Please keep in mind that it's ONLY radio people that think this. Listeners don't "associate" anything like this unless they have prior experience to draw on (like if their fave station in a different market they lived in was called something). Besides, Radio has over-hyped the audience so much by now that they barely believe anything you tell them anyway (WE'RE NUMBER 1111 *beats chest*).
You don't just change the name because the station has evolved (rather than flipped). Do you associate the word "apple" with computers? Is it because that's a word to describe computers? Or is it because their superb level of branding makes them one and the same? If anything, Radio stations need to learn how to better brand their products, and stop worrying about semantics.