Also when Alliances are added, we need to move on the diplomacy front too other then just attacking. Like trade routes that give each trader a certain % of the others gold intake per day. Maybe some modifiers for more Powerful empires that trade with smaller empires.
IE if Empire Big trades with Empire Small. Empire Big gets a 5% trade bonus from the Small empires gold intake per day and so does the small one..
Or switch it around Big empire gets 5% from small empire, and a 2% trade bonus from a equal sized empire.
Hence making the smaller empires ideal for trade and not having huge trade empires of only big guys.