Makes me wonder if PLAAF will ever get a small batch of the Su-57 just to compare its kinematics and avionics with their own stuff.
Trials don't require it, given the current trajectory of bilateral relations (courtesy of kind US&EU support) - at some point, we may simply get to mutual trials and exchanges b/n two countries.
The question with su-57 is a simple one - does PLAAF/PLAN need a specific flanker replacement, or flanker fleet (with its rather special set of qualities) will be replaced entirely by different local solutions.
Not sure PLAAF really needs it, but then again - it
always was the case, yet now PLAAF is the world's most prolific flanker operator.