The AO rating seems quite extreme. I wouldn't recommend this game to young kids no matter how much blood and vulgarity they removed (it's still a game about amassing an army and slaughtering people), but AO goes far beyond that. In the US and Canada, you can have blood sprays, profuse vulgarity, nudity, and just about anything else and still only land an M rating. AO is reserved for things that we're concerned about even adults playing, usually pertaining to deviant sexuality (violence, prostitution, etc.). AO means you can't find it on the shelf in any store. It's a death sentence.
I can understand why Korea wouldn't want to show smoking everywhere. Seriously, do we need to try any harder to convince kids that smoking is "cool"? We already spend millions of dollars trying to get adults to stop smoking and billions paying for their health care. I would hope that didn't tip the scales into making it AO, but I can see it being on the list.
Vulgarity, well, let's face it -- our kids learn to swear before they learn to play video games, and they usually learn it from us. The war against swearing is a global hypocrisy: we all swear, yet we insist children not swear and that we not swear in front of them. And they are just words after all, albeit ones that we associate with some strong emotions.
In the end, it all comes back to the parents. Game ratings are supposed to inform parents what to expect so that they can decide for themselves. It only works if the ratings boards give reasonable ratings (AO for profanity and smoking is hardly reasonable) and if the parents consider the ratings (as a lot of parents famously did not do with GTA IV).
