No, I don't think we need more WA’s personally. Wario and Waluigi are just fine as is and even the latter was slightly pushing it a bit, even if I do like him. I would rather see new female characters and/or have underused characters like Mona, Ashley, Goombella, Shokora or Captain Syrup appear than WA versions of already existing characters. If Wario needs a female partner, well…Mona is right there and ripe for the picking.
That said though, I'll be lying if I said I'm not down with those concepts, because those are really creative and fun.
If we get designs like that in the games (which let’s be real, we won't), I’ll probably be accepting of the idea, even though I would prefer new or underused characters instead.