caveat: 5 games in and I have to commend you on the depth of play and strategy, it's genius. That said, the follow idea is certainly not needed for a complete experience, it's a "what if" scenario.
What if there was a hardcore mode where player to player messages had to be sent by fast courier (distinct looking sub icon at 2x or similar speed)? Maybe even have the a more limited radar? Can't tell who owns a base out of view, can't see how many drills a player has or what their production rates are... Stuff like that.
Totally a what if, future feature kind of thought.