Koshiki no kata has a different sort of feel to it than the lower-level kata in judo. Not exactly less precise-feeling, but perhaps vague might be the right word for how I feel about Koshiki. The lower-level kata such as Nagenokata and Goshin Jutsu (if that one is even a kata at all) have more of a technically defined, rigorous feel to them. Sort of a, "Put your foot right here and do exactly this with your arm..." sort of feel.
Sure, Koshiki has technical standards, but they seem to have greater flexibility within the standard than do the lower kata. Greater allowance for different masters to express these techniques and principles their own way.
I suppose part of this is that you can't really stand on the sideline watching a couple of red belts in judo doing this kata and then tell them, "No, you put your foot wrong there, and you should have pulled more like this..." By the time you get to the point in your judo career that you should be working on Koshiki no Kata, you've pretty much already figured out how to do all the principles expressed in this kata.
Learning and practicing Koshiki no Kata should be more like getting reaquainted with a bunch of old friends than learning new principles and techniques.