It has come to my attention that Galciv2 needs borders. All nations have borders. All through out history there have been borders...and if a hostile nation crosses it, well it won't be pretty. I KNOW about the ring of "influence", but it is not a border. It makes no sense NOT to have one! Technically you can't own space, but in all good sci-fis there are borders to say "hey keep out" or "I'm bigger that you! Stay out!".
To me, It seems kind of fishy when enemy ships are going around your planets to get at the enemy on the other side. Wouldn't YOU want your space to be free of alien ships? Plus, it would create fun and challenging scenarios. EX:The biggest civ is in the middle of you and your enemy. You can: 1) Go through their borders and risk retaliation 2) Go Around Go Around! 3) Anything else you can think of!
BUT... I'm pretty sure I'm beatin' a dead horse here, so POST AWAY!