This sounds crazy, but /r/sino on reddit is pretty much as close as you'll get to mainstream Chinese political thought in English. There's a very good chance many of the people there are legitimate shills for the government, but I mean, those are the state-sponsored and permitted opinions that they're presenting. People going against the grain either don't talk or get silenced.

From an American perspective, the stuff said there is absolutely bizarre and contradictory to virtually every talking point you'll hear from everybody else, but it aligns very closely with what people I know who live in China/still have strong ties to China say. Expect lots of cherry picked data and extreme reaching just to prove a point. Though to be frank, that's politics everywhere.

If you're frequently caught up in American/European politics, a few minutes of reading discussions there might frustrate you, but it'll also make you think because the viewpoints are so contrary to what most Westerners regard as the norm.