I understand the critics against the subjective criteria like "Look".
Look means: the ability to create a native app which is at least beautiful as modern WebApps.
e.g. Slack or VSCode (Electron) are beautiful, while fractal or NoteCase (Gtk) are not.
As i wrote in another reply you probably want to rename this to themability (or customizability, but that can be a bit vague whereas themability is a common feature that one may want from a GUI toolkit) instead of look.