Simple vs. complex has been an issue for sometime between the western philosophies of aircraft design that is also needed to have a 20 or 30+ service life.
As for the Russians or Chinese their biggest issue has been around systems design, development and integration for these aircraft and not aerodynamic. Unfortunately as the west has transferred its manufactory capability to China including advanced computer manufacturing, this will not be the limiting factor anymore, as I am sure the Chinese are very adept at copying these technologies and transferring them for other uses.
In the end it will be a numbers game of who can shoot down the most aircraft by any means possible to gain air superiorly over the battlefield.
Now the big worry is that the Russians and Chinese are not as politically restricted to whom they will sell their weapons technology to, unlike the west that is restricted for one reason or another, including to other friendly partners.