I was totally envious watching Tom's swing during this year's British Open at Turnberry. I was also proud and happy for him. I have not seen anybody our age -- he's actually almost 10 years younger than I am -- swing like he did that week. Every swing was a complete swing. He finished his backswing beautifully, he had great transition, and he swung with the same tempo for virtually every shot and every club. It was fantastic.
The pictures on the bottom row, here, were taken only two weeks before the British Open. I believe, however, that his stance was slightly wider at Turnberry -- maybe subconsciously because of the wind.
You see a very similar shoulder turn -- the secret to Tom Watson's golf swing -- in 2009 as compared with 1980. He coils his body more than any of the top players I've seen in a long time. He presses his weight into his right side so he can push off of it.
One reason Tom plays very well today is that he is not a position golfer (neither am I). Rather, he lets his body react to the swinging of the club to generate power. In 1980, he had to figure out how to get the ball in the air because the golf club itself wouldn't get it there. That's why you see more of the reverse-C and his head farther behind the ball. The driver and ball today are designed for more launch angle. You can be more on top of the ball and still launch it. If you dropped a ball from his left eye at address, in the 1980 photo it would land back of center in his stance. In the 2009 photo (see above) it would land much closer to the ball. At the British Open at Turnberry, his head was very stable all week. That's one reason he drove it so straight.