On the day FitchRatings (majority French owned) downgraded the outlook on US rating, it had also released a statement on China’s single A rating and how it was contingent on rebalancing occurring. There was also a small research note attached to that press release. Both were useful. The media ignored that, (un)surprisingly.
In fact, the sense one got that if the US AAA rating was undeserved (“The U.S. is the most heavily indebted ‘AAA’ rated sovereign, with a gross debt ratio equivalent to double that of the ‘AAA’ median.”- Fitchratings), then China’s single A rating too was rather undeserved and based on the arguments that Fitch had put out and on the basis of the evidence of the last two months (credit spigots opened up), there were both necessary and sufficient grounds to downgrade China or at least put its rating on a negative outlook already.
You can find Fitch press release here. It contains the link to the underlying report that has the analysis.