I find this an unfair criticism.

This is trained to upscale anime images and not woodblock prints - and anime images are typically flat, uniform colors. This may have issues scaling up a still of a background scene from 5cm/second but would fair much better with a character still from .hack//sign. You have to keep in mind what it is trying to scale up.

>(Naturally I could train a new CNN to do this, but it may not even be necessary!)

Training to upscale woodblock prints and retaining the texture might make sense if you care to retain texture. It only works as well as it does because the style is very similar.