I would like to see a plugin or add-on that will let you talk to other players that are close by but tuning in a frq into the radio just one set aside that can be used to talk to passing players or following players/groups make it with realistic range as well.
I remember seeing a mod that did something like this somewhere, but I can't remember its name, and I tried to find it but couldn't...
I'm not sure if the one you are thinking of is MSFS specific or not, but this is one I downloaded at one point when I was back on P3D:
It's simconnect based and doesn't specifically state that it's compatible with MSFS, so I don't know if it would work with it or not. Haven't bothered to try it.
Some form of communication between players would be nice though.