I want to explain why I think you are wrong in terms of it being thought out. I think it was very carefully thought out and it fit into his plans very well. Whether it was "brilliant" or not I suppose depends on what you think of the game he is playing.
If you carefully look at Snowden's actions and his statements to various press establishments, his entire strategy is based on playing one group off another. He got the Washington Post to publish a story on Prism by getting the Guardian to run one on the Verizon warrants, for example. If you look carefully he is doing the same thing regarding Hong Kong.
1. He went to Hong Kong and immediately made provocative statements about the commitment of the special administrative province to the rule of law and to political dissent. This does not mean he believes that this is the nature of things. What these statements immediately did was put the image of Hong Kong's independence at risk of Bejing comes in too forcefully.
2. He then makes a number of statements about US intelligence activity which, quite frankly, everyone would probably assume to be the case anyway (hacking Chinese internet backbones etc). This creates a US vs China dynamic and shows that he can be a danger to the US if the US does not back off.
In essence what he has done has been tailored around Hong Kong specifically. He has chosen somewhere to make a stand that fits his strategy, nothing more and nothing less.