Re: JL-15 and other trainers
For me, Guizhou should take advantage of all the previous technical improvements already developed in China by Chengdu and Shenyang for the J-7/JF-17 where applicable, like auto-maneuvering slats, DSI intakes, better radar and avionic options, an in-flight refueling probe and more powerful engines.
Take all of that and then develop it as a single seat version for the ultra-low end market.
There are still a lot of countries out there that operate the MiG-21 and this highly modified version may appeal to them, a simple easy to operate and maintain aircraft that is familiar and rugged with an established maintenance and support infrastructure.
It will also help to keep the production lines in China open and provide basic air defence for those with a very constrained budget.