We all assume they want to make people like Crystal, so they decided on an old iconic designer, but why not Itou-sensei. Yes, Kazuko Tadano is the original designer and anything that followed was based on her work, but Ikuko Itou worked on the show the longest of all three character designers and her designs are probably the most iconic 90s look. Then her artwork was used on a lot of merch, including a 2019 calendar. Kazuko Tadano is not a bad choice, but why her? I know the obvious answer is availability, but I want to see other possible explanations, albeit speculation on that matter. Also just out of curiousity which one do you prefer personally based on their work on Sailor Moon alone?
I'd argue because Kazuko Tadano is just slightly more iconic when it comes to "nostalgia" Sailor Moon. When you think of "Sailor Moon" most people think of Classic and R first, then the later seasons.
Ikuko Itoh's art is great and iconic, too, but in later seasons, she started making characters' ears stick out more and bigger. It was
excessive in S (one of the reasons why I don't like that season), although she did dial this trait back in the Super S Finale. Thus when you think of Itoh, your mind snaps forward somewhat, because as critical as she was to the two-part finale of Classic, her influence on the series went forward for several more seasons.
I'm biased, though, because I prefer Tadano. Even in earlier episodes, when both worked on the series, I prefer the way Tadano drew the characters. I will admit, the
colorists who work with Itoh (I assume she's not coloring her work herself) do a better job.