Heres a pic to help illistrate.

Ok you have Fields A,B and C. A is obviously the most important base to have as controlling it gives you the possibility to take 3 different fields where as B and C are less important with only 1 capture point. If you lose A then you no longer have an option to take E unless you get A back or work around and get I some how. Farther on you have a choke point at J but if you get J that opens up alot of options.
And I konw some like those super sneaky long range runs so say we leave N with the CAPTURABLE BY ALL option checked so if you are sneaky enough you may take these types of bases wheather or not the have a point leading to them.
You can fly or drive from any field to capture a base at the capture point. Or just furball between a couple bases that don't have any shared capture points.
Not to meantion people would have an Idea where the attack might be going next unless it was a base that had lots of points from it. Though bases like that would be a huge target for attack.

I think this type of play would promote teamwork... I've seen alot of missions created to take the current zone bases and may great fights evolve from those take attempts. This gives fields more value than we have now.