Complete weapon overhaul
Better and more realistic explosions, boom size affects the explosion effect, no more giant rock spewing from the bombs. Shockwaves, condensation effects would be cool.
Destructible buildings would be cool, more missions involving new types of weapons.
Nuclear bombs, with a cool flash, shockwave, mushroom cloud, capable of being detonated via impact, time delay, or barometric height trigger. These would include a new nuclear bombing mission, in which you would have to defend yourself/another bomber to drop a nuclear munition. There would be a different effect for airburst/groundburst
Custom bombs should be easier to make. We should be able to add things like self destruct delay, airblast, parachutes, etc. This could also include things like explosive fuselages and a way to connect blocks like parachutes tho the block to activate after they are dropped.
Cannons and Guns sound overhaul, or if they had 10 sound effect presets to choose from, this could also apply to things like engines.
Laser guided missile, and Laser guided bomb. The laser guided missile could be an opening to make more realistic ATGM's on vehicles. Laser guided bomb would act like your standard GBU or JDAM
Incendiary weapons, napalm and white phosphorus, just because they would look so cool.
Preset in the inferno missile to enable an arch attack (like a real hellfire)
Aerial Naval mines, could be used in a naval minelaying mission.
Cluster bombs, including the classic ones with the fragmentation sub munitions and the ones with the anti tank sub munitions.
Manual guided missiles, like the AGM bullpup or 9m14 malyutka.
Thermobaric munitions
Resizeable rocket pods, and resizeable rocket explosions. Realistic effects, and trajectories
Aerial auto lock turrets, for helicopters, WWII planes and such, as of now you need to know complicated coding and variables in order to replicate this.
I saw another post wanting to include realistic cruise missile presets, such as terrain hugging, sea skimming, surrounding awareness ( not sure who made it)
Slower missiles should not crash into the ground when chasing a target, this happens at lower altitudes.
Ability to lock onto the sun, you can use this as an advantage in dogfights
If there isn't anything listed with weapons, and you can think of anything else that would be a cool addition, try to think about it, because all weapons R Cool