I've always thought great footwook behind the plate is what makes a catcher stand out from above the rest. Anybody can fall forward and block a ball in front of them. Pudge had the best footwook of any that I can remember and that's what made his defense over the top of the others.
As far as the knee savers issues, I ran hurdles in school, so I did several strecthing exercises before and after a race. I've also competed as a catcher in adult leagues for quite some time and have continued my basic stretching program before and after a game. I have never used the savers and never had problems with my knees. I also spent a good deal of my working career on my feet. I did some type of stretching exercises for my job. I don't know if they have helped, but I don't think I would able to do as much athletically as I do today if I hadn't of continued.