I like her villains being more eclectic. I've heard suggestions in the past suggestions that they should only use mythological villains with her but I think that limits the story too much. Maybe there's some vague theme to tie them all together, but I'm not sure what it is. I think it's kinda reaching to put a theme to all of Superman's villains as well.
I don´t. Themes can be nice. I also don´t reduce all Diana´s villains to mythological, nor would I want them to be.
My suggestion was the theme connecting them was psychological. They were all guided by an obsession and distorted forms of love which were like the inversion of Diana´s love.
Superman is easy, all his classic villains, are Gods like him, except they´re corrupted by there Godlike power or intellect.