Add a new dimension to the game with diplomacy and politics.
I suggest 5 levels
2: full allies. A fleet can orbit an allies planet. Allies can not attack each other. Scan information is shared. Can trade unlimited tech
1: friendly. can only trade 1 tech each per cycle.
0: neutral: This is the default status when 2 empire are in scanning range. The level has to go up or down before the next cycle, if not up, then down automatically on the next cycle.
-1: hostile: can’t trade any tech. Hostiles can attack each other after which they are
-2: at war: this is obvious. To end hostilities, players can agree on a cease fire. A player can offer 1 techtrade or money, resulting in status neutral. Or more techtrades or money, the result will be status friendly.
A raise in level can be initiated by any player but would have to be accepted by the other player.
A drop in level can be the result of any players action.
Also, an ally of an ally should be a friend at least. So if your ally A has an ally B, he is automatically your friend. If you drop the relation with B to neutral, your relation with A automatically drops to friendly.