In-depth antenna broadcasting\recieving settings.
The ability to broadcast and receive messages at user defined antenna frequencies and filters.
This could allow factions to set up entire secret communication networks, just by tuning in to the right frequency using the right filters and modulation types (For example: Amplitude Modulation and Frequency Modulation).
Also public radio stations using a messaging or voice chat system could be fun. You could join a huge faction and just role-play as a radio host/operator; playing music, news or status updates for the fleets/bases in range.
This could also add other stealth elements, for example you can only see enemy ships if you are in range and you are using the right frequency and they are using a normal antenna, not a laser antenna.
If you are at the edge of the range of an antenna, voice chat and cameras using that antenna could gradually become lower quality before cutting to static, for immersion and so that you know that you are getting dangerously close to losing communication with them.
Of course people probably could make radar jammers with programmable blocks and antennas as a form of denial of service attack for these secret radio networks, or they could just listen to faction plans and communications.
Also if this went far enough, this could even apply to drones and such. If an enemy knew which frequency your drone antenna's operated at, they could possibly access your ship through the antenna. Whether they would be able to access other blocks that they did not have permission to use would be up to KSH. If they could, you could try to sabotage enemy operations, (For example: An automated mining operation using slowly rotating pistons could be sped up to the point of instability, slowing down enemy progress.)
Of course this is a huge update, and if added would probably make sense to be added near to release, when servers can hold many more players at a good simulation speed.