Yes, because McCoy is awesome (and so is Urban).
What they did to Cyclops in the X-films completely ticked me off, too.
Co-signed on both points!
I suppose an analogy closer to home is in the TNG films, and how the closest thing to a "Big 3" for the show was Picard/Riker/Data, but somehow in the films Riker was traded in for Worf. It was that way for the promotional materials, and it carried on to the films. It's not that Worf had more to do -- he functioned the same way in the show -- but rather it was that Riker had less to do!