Years ago... long long ago...may be a better start .. Planetcide had the same problem all capture type games had.  You could go way behind lines and capture a base or tower by yourself.  This made the other side furious as they had to divert attention and recapture that area far from the front.  Then Planetcide team must have seen WWII Online.  Here they had the same problem but the Devs figured out that the front line had to be the front line and invented No Link no Capture.  That is if your next system does not have a link to your side it is not on the frontline and you cannot capture there.  Voila!  A decent game is born.... 

Amazingly it allowed both games one with money.. Planetside and one without Battle Ground Europe to stay around and remain interesting.