I really think you should flesh out the intelligence market into it's own ughh... thing. To my understanding comm relays are a place that collects system wide information and broadcasts it around the system and to other systems. Each faction will have comm stations of their own (and maybe some independent ones) where information that group receives is gathered.
Here's what I think, there should be levels of intelligence ranging from low which anyone can see except enemies of the faction eg. planetary weather, right up to high level eg. future battle plans. Being friendly with the faction will access higher levels as will planting comm sniffers of varying levels. This could lead to all sorts of dynamic espionage missions such hacking one factions comm relay and selling the information to a rival faction or scouting a planet for information to give to a faction.
Secondly I feel that comm relays are too valuable to be left alone. They should be guarded or the surrounding space be considered out of bounds and being in that space will prompt a faction response if seen. Instead information will be received through a news interface perhaps and in turn placing comm sniffers will be more risky but more rewarding.
Finally something that isn't really related to comm relays but I feel some sort of visibility system should be included (just a simple one), smaller fleets are less detectable or something. I only bring this up because at the moment, the way I see it, the safest way perform a stealthy bugging mission would be to assemble your entire fleet and take those motha's head on which just doesn't feel right.
Please tell me what you think and I don't expect this in the next update, this is more of an overall plan.
Oh and keep up the great work