Suspect the Rhumba format will stay on 1430 (perfectly fine coverage for most city of Boston Latino urban neighborhoods) and the big 1200 coverage will be reserved for something more mainstream, like a clearing point for all the Premiere shows. And yes, it is possible that CC will take this new, big signal and spin it off. They could probably get a pretty penny for it after the upgrade is done.
By the way, NPR is not actually operating in the same arena as the right wing talk shows. NPR, for all the chatter about how "liberal" it is, is actually pretty balanced. They almost always have two opposing guests represented in the news longform. Their signature talk show, The Diane Rehm Show, almost never has one guest from one side, and Diane never goes on a theatrical rant about how terrible, evil, and un-American people of a certain political point of view are. They tend to come down pretty centrist these days, with a humanistic bent (which some people think is a liberal trait). The biggest complaint is that NPR is dull, but dullness is usually a result of balance which is the very reason why commercial talk radio avoids balance and goes for vitrol and name calling. Nothing gets ratings like vitrol.
For some reason, the Liberals have never been able to match the Right-Wingers for creating the winning combination of demonizing, entertainment and synthetic patriotism on commercial talk radio. Randy Rhodes has the vitrol all right, but not the other ingredients.
Ed Shultz is the closest yet, but he needs a TV show or a cable deal (like Hannity, O'Reilly and Beck) to increase his visibility and commercial
capital.