Complex sentence: Over the course of several years, this original costume illusion saw occasional use or was not incorporated, by various illustrators in different stories, with no standard for whether it was an official part of the costume anymore.
Split into simpler sentences: Over the course of several years this original costume gimmick was occasionally used or ignored by various illustrators in different stories. This was due to the absence of any standard as to whether it was an official part of the costume anymore.