I think people generally underestimate the complexity involved with modern avionics. In the case of the F-22, 90 % of its 1.7 million lines of code is associated with its sensors and radar There is a big divide between AESA and older radars. The strength of the F-35 is not in its stealth but in its sensors - the type that requires 8 million lines of code. Even the Typhoon tranche 1 needed 1.5 million lines of code.
I personally understand that principle, but I question the nature in which the practice of more complex avionics may prolong or complicate things such as integration of new systems.
The degree to which a system is designed to be open architecture, modular, and/or the way in which different systems may have been designed or implemented to mitigate or minimize mutual interference are confounding factors.
For example with JF-17's Indra EW pod, it is likely that whatever AESA they end up choosing will have the requirement to be compatible with the pod itself (there's two Chinese AESAs and one Italian AESA in the running from memory).
Additional, systems such as SABR which are offered as off the shelf AESA upgrades for fighters equipped with legacy radars, where those AESAs can replace legacy radars with minimal back end processing changes.