Yeah that is the logic behind moving the ball back in the stance. Or a cheat as you like to say.
You can also hit a big pull slice with the hands behind the ball and possibly a normal slice also. If the clubface is square you can hit a straight ball with hands behind the ball. The tendency would be to pull and hook as you mentioned because the clubhead passing the hands tends to cause it to close down.
I believe also that if you get your hands as far in front as Gainey has his you can hurt your wrist big time if you do not release correctly. That is what I noticed anyway. If I felt like I kept the trail wrist bent back right to the finish and did what I think of as a windshield wiper release then I had no problem.
Have you used HSS recently just for some fun?