Why was the head of the PLA Military Court promoted?

Major General Liu Jixing

China watchers are talking about the list of 16 high ranking PLA officers released on January 15 by the PLA, who are being investigated or have been convicted of corruption offenses.  According to Chinese media, is the first time that this has been done, and the government motivation for doing so is also being widely discussed.
A side issue to the story is the PLA Military Court, the court that will likely hear these most of these cases.
On January 14, 2015, official Chinese media announced that Major General Liu Jixing, president of the PLA Military Court had been promoted to at the level of commander of a major military command.  He graduated in 1983 from what is now Southwestern University of Political Science and Law, one of China's leading law schools.  He had previously held the rank of deputy commander of a major military command.  The head of PLA Procuratorate, Li Xiaofeng, was previously promoted to the same rank at the end of last year.  Official media suggested that the promotions are likely linked to the future trials of those 15 high ranking PLA officers.  
Last fall, two additional vice presidents of the PLA Military Court were appointed, with media comment that it was needed to strengthen the corps of senior military judges needed to try the most major PLA corruption cases.  
For the reasons discussed here, trials in these cases are unlikely to be public and the judgments are unlikely to be uploaded to the Supreme People's Court case database (discussed here).  The January 15 announcement revealed that Chen Qiang, former deputy head of military unit 96301, was convicted in May, 2014 of corruption offenses by the military court affiliated with PLA General Headquarters (see this description) and sentenced to life in prison.