The problem isn't that big economies get to spend more, it is that when EP spending levels get too high it breaks the game. For example in BirdNES the strongest nations were regularly getting to spend 15-25 EP per turn. Unrealistically, they could buy and do anything they wanted. It was apparent that it would soon be difficult to even spend that quantity of EP in a turn. There should be rich and poor nations but being rich shouldn't exempt that nation from the consequences of squandering and wasting its wealth. Maybe I need a "national upkeep" cost that represents the increased expense of holding a rich nation together and functioning. Great national wealth should have an element of precariousness to it.

. Ancient governments didn't really prime the pump of the economy, most they did for centuries was build infrastructure and conquer land.