I disagree that the call letters mean nothing, at least in this case.
There is something to the call letters, and if nothing else they include "NY" for New York, and are still familiar, and therefore memorable to millions of potential listeners.
Even if the new format doesn't follow one of the legacy formats associated with those call letters, NBC probably did some research and had very good reasons for picking those call letters in the first place like: Your New York, as mentioned above.
Those reasons are probably still good reasons today, and two of the big programming guns on the new Merlin team, Walt Sabo and Pete Salant were in positions where they would have known those reasons for for decades, and Randy Michaels, the biggest Merlin gun, probably knew those reasons too just from talking to other programmers in the industry over the years.
It's going to be interesting to see exactly what the new stations sounds like and whether or not Merlin has managed to create a magic fog that threw us all off on what they were really planning.