Excellent stuff!

I'm totally with Greg on this one, the mechanics of your swing should be the same and you want to swing with a lot more power than you probably think you need. Once you're hitting bunker shots more consistently, the confidence to hit them harder will come.

The "arms only" theory, I think, is used to try to ensure that the body angle remains constant and the head remains still . The bunker shot is extremely sensitive to small variations in the vertical position of the hands. A small dip into the shot probably results in a lot of sand being moved but the ball staying at your feet. Conversely, lifting as you hit the shot means that you'll probably catch it thin and fly the ball way over the green. My swing thought for bunker shots is to make sure my spine angle is constant and my head steady throughout the shot.