Back in the 90's WBLS used to be called "Power 107.5 WBLS", although I don't recall exactly when they dropped the "Power" moniker. Obviously that is no longer an option as we have Power 105. With the acquisition of the Kiss talent, I think they should use it as an opportunity to create new imaging, while still keeping the WBLS calls. "107.5 WBLS" sounds so mundane. Maybe something like "Magiq 107.5" similar to Atlanta.
although I lived in Europe through most of the 90's I don't remember WBLS ever being Power 107.5 WBLS and I followed urban radio in NY pretty closely. Do you remember what years they might have used that moniker? I tried to find it online but couldn't find anything.
I know PLJ used to use the Power 95.5 moniker back in the late 80's when they were more top 40 and competing with Z100 but obviously they dropped that a long time ago.
Other than that I don't think Power has ever been used in NYC.
In this day and age using call letters as a moniker for a station is rather lame but rebranding WBLS might be a risk. Everybody in New York has heard of WBLS since it's such a heritage station and the last thing you want to do when trying to gain listeners from another heritage station like KISS is rebrand into something unknown especially for the age group that fits their demographic.