This certainly flies in the face of what Brian would call the theory of the "freeturners." Awhile back there was an interesting thread where Brian detailed what happened when he actively tried to stop his pivot at the ball, in an attempt to
really snap the chain.
Though he advised against trying this, Brian mentioned that he hit the ball farther with the stop than with a "freeturning" swing.
My take is, you use the pivot to hit the ball, but part of using the pivot is allowing it to snap, sending the arms, hands, and club whizzing through the ball and up onto your left shoulder. I always thought Couples was the best example of this.
But back to the "freeturning," or pivot-only hit (whatever you want to call it). Here's
Hunter Mahan, a guy many point to as a "one-plane," "freeturning" golfer.
As you can see by watching the video, he's not hitting those laser fades with an uninterrupted turn. The hips clearly slow down, appearing to stop even (though the ball is gone at that point).
You also mention the crossover. I think almost all the guys who hit it long and solid release the club pretty hard. I mean really roll that sucker. I know different hinges work better for certain swings, and that may be especially true for pitches and chips, but I can't help but feel that most pros roll it pretty hard for full shots. Especially the longer hitters.