I've never entered a quilt in a show, but over the years various family members as well as myself have entered other things in our local county fair.
I definitely agree that the categories can definitely be problematic. One year I entered a counted cross stitch that I had put many hours of thought and struggle into combining elements of two different patterns into a single fairly large picture. The category was won by a small kit entry. I did not begrudge her the win as it was very well done, but would have liked to have been competing with others who had at least partially done their own designing. However in a small show that doesn't happen...most likely mine would have been the only one in the category, so no competition possible.
What was ironic was that same year I had purely by chance had an amarylis that I got on clearance after Christmas burst into bloom at just the right time to win best in show in the houseplant category! Go figure...no skill or anything went into that one.
And I know that personal preference is not going to go away in judging, particularly in the art categories. My best friend and I have observed for years that if it is not a particular style or subject matter then that piece of art work won't stand a chance at our county fair. And it's not even always the same people doing the judging.