Howdy!
The existing system is a base image with up to like 20+ mutations layered over the top, depending on how many mutations the player has obtained. Since the player's height being changed would change the base image, it would mean basically all of the mutation artworks would need new variants, which isn't feasible at the moment, since I'm the only developer working on the game and all artwork is on a commission basis. It seems unlikely that it'll make it in, but I've made a note of your suggestion and I'll chat with the game's frequent artists at some point and see if there's an easier way to implement it. Thank you for the suggestion regardless!