About the rudders its very possible you have the wrong expectations of rudder control, at least in the game. Rudders do have their place but dont forget many successful sticks fly with only computer mice, and/or, just a stick. Rudders are mostly used in taxiing, little corrections in a fireing solution, I use them for little corrections in a dive when bombing, or when stall/low speed turning a reverse rudder will keep your nose up. But generally a lot of the high "G" turns, dives, and climbing you wont use rudders at all.
And its very true that rudder control is much more sensitive at lower speeds, as they were designed to be. So its very possible your rudders are working fine and its your expectations that are in error. I went thru the same thing when I bought my rudders. And now? I use them correctly without even thinking. I suspect that often you are leaving your feet on them for no reason and applying rudder when you dont mean to. I still do that on occasion and have to catch myself.
