Why is the anime in watercolor? Not only does it represent childhood and innocence, but the colored pictures to the manga are often in water color.
Yuki has gotten a lot more feminine looking, right? Aside from growing her hair out, ditching her makeup and wig, and Art Evolution, she's most likely on Hormone Replacement Therapy so of course she's going to look more feminine over time. Just look at any bio-girl that's gone through puberty, or a lot of trans women over time.