This not only gives the player some incentive to play tall and expand cautiously — less they sacrifice unity, but is a very, 'very' minor nerf to larger empires that have enough firepower to level half the galaxy anyway. The problem I think you're having is mixing real-world logic with game design, something I'm often very guilty of even in this thread. Regardless, choices are important and giving players options is good game design. You can have less unity and more land or you can have more unity and less land. Think of it as... overextension.