There used to be a chopper called the Vario Clipper, made in Germany. I still have one that I have chopped thousands of feathers with, with none of the problems mentioned above. It still may be offered in Europe, but sources here in the US seem to have dried up.
I think the secret to the Vario Clipper is that there is a slot that securely holds both sides of the quill, so the quill doesn't bend over when it is chopped. The only drawback is that the quill has to fit the slot. TrueFlight feathers fit, but once I ordered some other brand where the quill was too thick and they wouldn't work unless I wanted to change the width of the slot, which I didn't want to do.
No doubt some clever person could add this feature to a different chopper, if he wanted to.