these two so-called 'deficiencies' are important in their eyes, but are NOT that important for China at these point.  When necessary, these two features can be added on the future derivative models, but it's not what China absolutely needs at the present time for the missions J-20s are going to carry out immediately.  If you talk about J-20A, B, Cs in the future, maybe.  But that's 3-5+ years later.  When you need a mailbox, you don't build a house.