I have a question for you You are a really really tall dude, how big a part is bending your knees in your game? I am just 5'10 and I realize that the more I bend my knees the better my shots - now that surely can't be due to height alone because I guess bending your knees gives you that extra power from the legs when you push up and forward but still. And you as I mentioned are pretty tall, what do you do for slices and low bouncing balls? Just bend your back down to reach or bend your knees?
Well - I see your knees trouble you but what do you think the effect would be had they not been troubling you and you could bend them as much as you like?