As far as i figured out, the big step into the next generation of combat aircraft should have an implemented suit of sensors, and processors to provide the pilot, either remote or aboard the aircraft, with a comprehensive tactical presentation, based on the data received from all sensors, after the computers makes up an hypothesys with all the data collected by it´s whole sensors-datalinks, insead of different displays overloading the pilot with information.
Different passive-active configurations, wich would however require an extensive work by the intelligence community to get the data on any potential enemy weapons system. Basically, a greater integration of information within the own aircraft and any datalinked systems.
The aircraft would have, of course, different degrees of stealthyness, powerplant, performances, weaponry etc, but it would be throught those systems that future air combat should be decided given the lethality of modern AA weapons. As allways has been in air combat, first to see, first (at last) to kill.