We can replace bear form with werebears and owlbears. All the travel forms have a whole menagerie of options. Poor moonkin has just a choice between two chubby birds.
I’ve never liked the moonkin form, so I always have the glyph of stars to replace it with the celestial model. But what I’d greatly prefer is an option to replace it with the currently purely cosmetic Treant Form model - and maybe even an option to replace the Incarnation: Chosen of Elune with the Incarnation: Tree of Life model.
edit: I am aware, of course, that the treant form was originally the healing form and that its inclusion as a cosmetic-only form is really just for resto druids who liked having a form.