When you concentrate on one aspect of the swing something else is affected. In this case one tends to take the club inside when concentrating on the rotation. Outside is a better path than on the inside. Some Pros do the loading but they still rotate through the ball. Not only do they rotate but also if you look closely you will see that the rotation is made over a stable left side.
All power comes from having a fixed point in the swing to rotate around.
If you slide, the club head speed will only be relative to your hand speed. A fulcrum point is the fixed point that something moves around, such as the pendulum on a clock. The fulcrum point is the fixed point from where the pendulum swings. If that point were to move all energy would be lost and the movement would stop. Just the very best.