SAC's design has already been rejected, the CAC design is the one that will become the Chinese ATF. SAC's working on their own thing though, there are some rumors that they're working on a F-15SE equivalent, as sort of a low-cost 5th gen-ish fighter. There are also some rumors that they're going ahead with their rejected design, but modifying it to make it a fighter-bomber, with private funding. As far as 5th gen primary air superiority fighter goes though, the J-20 is the one.
I don't see many outstanding issues, at least not just from pictures. After studying this thing for quite a while, it seems to me like they took great effort to make all the components fit together rather than mix-and-matching various design concepts like some have suggested. This is definitely a test platform, but the final thing won't be TOO different, IMO.