Having played for less time than Pat but being old enough to remember when truly fast greens rolled in the 8's, I make the following observations.
1. If a ball is going to stay in the hole, the speed it is travelling when it reaches the hole will be about the same regardless of the speed of the green. One needs to hit it harder on a slow green to reach the hole, but it will have slowed down by the time it gets there. Find some footage of Nicklaus in the 60's and watch him die the ball into the hole. I have been a reasonable die putter for more than 40 years and I assure you the green speeds have changed while the holing speeds have not. The force of my stroke has decreased for similar length putts. .
2. Speed is in part a perceptual issue. When a fast green was 8, many players 3 putted by overshooting holes, particularly on downhill putts if they were accustomed to greens in the 6's and 7's.. We calibrate our strokes to the speeds we are accustomed to.
3. That said, I agree that the challenge increases as speeds increase and anytime the challenge increases, the better player receives an advantage. Until the speeds become so fast that they become too much for the contours of the green thus necessitating flat uninteresting greens, I have no problem from a playing standpoint with increased speeds or from the benefit given to the better players. The benefit is a reflection of their skill.,
4. The major downside is the increased expense in maintaining modern fast greens. But that genie is out of the bottle and there is work being done to try and lessen the costs. A lesser downside is that , if the greens are too fast, they can result in a slower pace of play. But even 40 years ago, people took too much time on the greens.