Interesting... I don't know that drums need another moving part, but bad bearing edges matter. Sloppy, flexible rims systems seem the rule rather than the exception. It's remarkable drums work as well as they do (when they do work well).
I know what you mean. When I built my kit I took super care in doing the bearing edges as they are so crucial to getting a good drum tone. I finally got it down... Good edges and good tuning go way farther then an expensive kit. However with an expensive kit like a dw you get good edges.