Interesting article, thanks for posting! While I agree that there has been over-extension with regards to infrastructure development especially in residential housing, one thing I think we should remember is the power the central government in China holds to change course when necessary, even when a crisis has not yet occurred (imagine living in a country that can ground all flights for a day with no explanation and people take that as par the course:
http://on.wsj.com/1wVToAd). A similar point on over-extension could have been made about US expansion in the 2000s being completely attributed to the debt-induced US housing bubble, but our government had no focus or institutional power to stop that until the crisis had already occurred. In this case at the governmental level, China, with its ability to set long term policy and pre-empt crises, might have a leg up.