Much has been made of the ‘Stack and Tilt’ swing this year. Mike Weir is a big believer of this motion. Personally I feel that the description of the concepts have been over exaggerated to help players develop the feel for the movement. Over exaggeration of the movement is a common teaching technique to help players feel the movement they are trying to create.
If you are trying to create better balance and consistency with your golf swing then watch Mike Weir’s swing. Pay attention to his left leg during his backswing. His leg stays in exactly the same position as it is at address. His left hip will rotate back, but his leg stays virtually the same as the start.