Forget about the paper tiger AMCA ... First sort the problems with LCA and if you aren't updated go check the related thread ... As for us , we are already developing J-2X with China so dont worry and option for J 20 is open ...
You forgot to mention (PAk-FA) FGFA i guess which is not so much on paper ... good luck on J-2X with China , so coming back to the point where i started there is no harm in using an already existing technology or partnering with others for development of weapons systems ... thats what both India , China and Pakistan are doing in different ways ... end result is the same !!!