Actually that's what's so fascinating. It's not necessarily about the thing that happens, it's why it happens- the intent. If Wax for instance, didn't have such a noble character, and decided that it's time to start using his mistborn powers for selfish reasons like to acquire fame, fortune, sex and other unworthy pursuits then not only are the books 'adult' but they are now teaching that it's okay to use great power for evil purposes.
Obviously Wax never does this, nor would Brandon Sanderson ever, ever do this with a hero. The reason we love WoK so much is Kaladins great desire to protect and defend others, even if a violent means must be used. Now, if we know a character is evil in the book, is it understandable that they do terrible things like the bloody torture room in Bands of Mourning? Of course, but the good, honorable people do everything they can to help, save and protect- we look up to them, and our children can too.
Back to Wayne's language. There is nothing ennobling, uplifting or encouraging about the scenes i described in the previous post. Did Wayne grow up in a rough fashion? There is no question. Is his behavior toward women ever presented in the book as a terrible thing, or something he is working on? No, it is not. If he ever said something like, "I know i shouldn't treat women so, but it's so hard not to" or some such then you can get the idea that this is not acceptable behavior. Wax does do this in Bands of Mourning by convincing MeLaan not to walk through the traps naked, but he doesn't explain why MeLaan should not do it, he just insists that he'll buy her new clothes.
This remind's me of Legion. There is a character that is constantly swearing but another character reproves them and encourages him not to swear and he apologizes. Which shows that while some people make bad choices, they are still trying to overcome those weaknesses and be good.