I've been experimenting with CTE after watching the DVD a couple weeks ago and I'm not sold on it yet, but it does seem to be very accurate at times. But you're right, John's not the best representative... you have to have a straight stroke to make ANY aiming system work. John doesn't, and he knows it - he mentioned in the booth afterwards that he misses a lot of shots due to stroking errors.
It is not just "stroking errors". The way he executes shows that he doesn't align correctly for the shot. The whole foundation is the problem. The movement he does at the end of the stroke is subconscious and he can't control this. Because his brain is getting a false perception. He has a lot of work to do with his eyes, feet, bridge placement, etc.....