I've just started planning our exit. 

No regrets, no negative sentiments about leaving China. 

I am a bit concerned about removing my wife from her native country, but she has lived a bigger part of her adult life outside of China than in China, so only a minor concern.

I need to have the MIL come visit us once in a while as she does make the worlds best dumplings. 

China is a good place to visit, but to live here for a long time is not a good choice for foreigners. So you probably made the best choice. 

I'm planning an exit in the medium term, 2-3 years. The thing about China for me is that of course China has it's good and bad sides, but the bad sides (traffic, pollution, smoking) really, really piss me off a lot and thus skewing my perception in a strong negative way. 

So all in all, I am filled by a strong sense of relief when I'm thinking about leaving. Do I have regrets? Honestly, yeah a little. 

Very good outlook.  If you want to leave then be thankful for the beautiful memories and experiences and look ahead to something greater.  I think there are lots of things we can learn from our experience here to take back to our communities back home and make an impact which is what we are on this earth to do.  

I haven't had this feeling. Ive been fine with my Chinese wife and family. I know how to fix my own problems or dislikes, you just need to be mature enough.