First be cool if we got thank you notes from local trench force for shooting down annoying balloon once in awhile.
Also get kill confirmations from ground forces.
Finally have a member of the flight at end of mission to tell you who he saw you shoot down, this before you put in claims. Currently it's as if the pilots never talk to each other. (I think there are a few ways to increase immersion between flights and giving pilots and squadron a personality of it's own, this being one of them and I'm sure it happened). Obviously these suggestions would be once in awhile events.
Arty is something that's a glaring hole at the moment in the game. I do hope one day we will see Arty batteries and actually be able to spot to a on map battery! I understand it would only be possible to show a very small amount compared to reality BUT just a few would be amazing. It's something I always notice the lack of after reading memoirs etc.
All are kind of chrome but would add to immersion.