A good example could be how Endless legend hit the nail on the head with open/closed boarders system. (along with the diplomacy point system, its practically a ingenious system for stopping tons of exploits and quirky AI stuff).
Now to avoid human error; if you try move a unit into someones territory that have there boarders closed then you would be asked if you want to start war.
In RL boarders and airspace are a very big deal especially were national security is concerned. Fly over Washington DC,,, one warning then your in trouble. Fly over North Korea, I don't even think they give warnings.
In gal civ 2 allot of my wars have been started just because someones ships kept flying in my zone of supposed control. Its like a stranger coming into my house uninvited and starts casing the place. Then when I find them start building star bases in my ZOC,,, . Its like the AI is saying , "hey I built a star base for you (troll face), do you wanna buy it from me or start a war with me and my ally? (grin)." I have always hated that element that I like to call, "starbase cancer", because you become the bad guy now and have to initiate war or be extorted and remain the good guy.
Open and closed boarders would also alleviate some of the AI's dumb decisions like building crap on our lawn just because they can and don't realize the percussion's they could face because the AI doesn't know what a boarder is. Diplomatic hits don't really hurt ya much if your casing there goods anyways because any good tactician knows what comes after scouts,,,, armies.
*It is said that if you know your enemies and know yourself, you will not be imperiled in a hundred battles; if you do not know your enemies but do know yourself, you will win one and lose one; if you do not know your enemies nor yourself, you will be imperiled in every single battle.*
The only real brain twister I can think up of is the scenario when someones boarders/ZOC starts surrounding your planet. Now you can't move a ship out without causing war but then again that's what happened to the humans per-say trapped on earth. Then again it becomes a personal fault issue because if that happens you must have been neglecting your culture and deserved such a fate anyways.
At any rate a conscious acknowledgment of boarders would make 'future espionage' and diplomacy necessary in a big way and also alleviates quirky AI actions that makes it appear suicidal while unintentionally forcing your hand at times. Lastly, a culture victory would no longer be the easiest way to win ether.
Now don't get me wrong, Gal civ is an awesome game as it is and is a true gem but the lack of boarder awareness really leaves allot of passive options/strategies out of the game. There is a shallow feeling about it at times. I guess the bottom line is simply this; the person who invented the wheel was pretty slick but not a genius, the person who utilized two wheels, opened a whole world of opportunity's, that's genius. Never underestimate the potential of small things because there easily overlooked. No pun intended Stardock, you have a great wheel.