The addition of the new weapons has exposed some issues with the default missions, there's not enough air defense. It's very easy to neutralize air defense sites that pose major risks to strategic ordnance or aircraft. My suggestion comes down to three major points.
1. More variety
It'd probably be helpful to introduce new air defense vehicles and structures, all with different operational goals and intents.
2. Better constructed defense
Most air defense batteries right now are unprotected outside of neighboring SPAAG and short range IR at an airbase, a defensive cluster that operates around them to assist in defense would likely be a good idea, say SPAAG, potentially C-RAM, and maybe short-mid range IR defenses, or short range radar SAMs.
3. Defense in depth/cross coverage
A core part of modern military doctrine is defense in depth, where no singular part of the battlefield is left undefended. Defenses exist everywhere, whittling down the attackers no matter how they try to attack, slowing them down and biding time. This, plus multiple air defense batteries being able to cover for each other to improve survivability, would likely make it MUCH harder to instantly take out air defense systems.