The majority of judges - and I've talked to and listened to hundreds of them over the last three decades - for the most part don't notice much about costumes beyond the color and appropriateness. They might notice something about the fit - too tight, too loose, too short or long - or wonder what such-and-such of a detail had to do with the music or theme of the program. IJS has a costume deduction for something that violates the rule but that's very rarely taken and almost always for either exessive nudity or the illusion of nudity or for a safety issue. In ice dance there's more emphasis on costumes reflecting the character of the dance. In fact, in the judges' education seminars I've attended, the judges have been strictly instructed to judge the skating, not the costumes. Color notes are usually to help the judges remember one skater from another - and unles the costume is distracting (and a lot of judges have commented that they find Weir's costumes take their attention away from his performance - remember the swan glove?) , they are too focused on all the other aspects of the program to remember much more than the color.
Basically the emphasis on costume comes from the coaches and the skaters, not the judges or officials. Skaters want to feel confident and for some, dressing well (or spending a lot of money) gives them confidence. Personally, I have my costumes custom made but that's because my body type doesn't allow me to buy anything off the rack; even when I was skinny, nothing fit. Skating outfits, like everything else in the sport, have become big business and I doubt if that's going to end anytime soon.
However, Theatre on Ice does have a technical portion of their competition which requires teams to wear simple plain unforms. All the ones I've seen have been black pants and black turtlenecks with no decorations of any kind. It's an interesting concept and really allows the judges to focus on the concepts that the teams have to convey without the distraction of flash and color. I heard someone describe it as the difference between modern dance and Broadway and that seemed apt to me.
I would like to see a trend toward less flash and glamour at least during the short programs and maybe the team competition at the Olympics will lean that way eventually. But until we see exactly what format the team competition actually takes, it's probably a moot point.