Even if she'd gone evil, this scene would have had problems, simply because it's not a superhero fight, or a hero-vs-villain fight. It's a guy backhanding his wife, and is handled as such. Frankly, I think it would have caused a lot less problems if it had been presented as a superhero fight, or, as Byrne suggested, he had simply used knockout gas on her or something. Hell, it's not like she's not been knocked out by her own teammates through similar non-physical methods before, and she could have still been angry enough to divorce him afterwards because of the violation of trust. I just think that by invoking something like straight-up domestic violence, it provoked a visceral reaction in both readers and later writers that gave the scene immortality in all the wrong ways, and could have been handled so much better.