Personally I would agree to have at least a substantial number of twin-seat J-15B (is that what we call the catapault version? or is it J-15T?) for better capabilities regarding anti-surface ops and interception, if the added empty weight doesn't impact the restrictions on carrier landing too much.They could have ported over systems from J16. I do think that carrier based heavy fighter should be twin seater. Much like the F14. You have single seater J-35 to clear the skies and you have J15 to do strike /anti ship and J15D to do EW.