Interesting point about the China trip from expert Minxin Pie, via Mike Allen:
What was accomplished: There may be a silver lining. Because the press coverage of his trip is quite bad, it may have caused some heartburn in Beijing. At the end of the day, Chinese leaders know that a good relationship with Obama (and a weakened Obama cannot manage U.S.-China ties effectively) will be in China's interest. So there is a chance that China will do something after the trip is over to show that Obama's visit is not fruitless after all.
Sounds plausible. One thing you can't emphasize enough is that, just as we're pretty sensitive to the domestic political constraints facing the Chinese regime, they're hyper-conscious of similar constraints on our administration.
Opportunities missed: I would say that he did not miss any big opportunities because there were none to begin. He did miss one or two minor opportunities. For example, insisting on a nationally televised town hall meeting in Shanghai (and calling the Chinese government bluff by threatening to cancel the event if it is not televised nationally), Obama would have scored a minor pr victory.