I think that the costs for the starbases should be way more than what they are now...both credit wise and resource wise. Not for sure on the other 2 races...but when I built my first one for the vasari last night, it cost about 1/2 the total cost of a cap ship. These are supposed to be much stronger and better than a cap ship...shouldn't the cost be proportionate to that?
Also, you should have a upper cap limit on the amount of mines that you can place and there should be a resource cost to place mines. I literally placed about 100 mines all over one grav well in about 5 minutes time. There was no way an enemy ship was gonna fly anywhere in that grav well without blowing itself to pieces.
Just some thoughts, and I will post this in the beta forum as well.