To me a bit more specific, BBs or DNs in my estimation should be worth nearly as much as a planet or even a number of planets in terms of map-based VCs. What I am essentially envisioning is a system wherein one or a number of these capital ship PvP kills could swing the entire VC standing of one side or another. Since these ships represent major economic investments, their loss should count for something. This would be different from, let's say, the SG3 system wherein the shear number of PvP-based VC points turned the tide in the VC points.
As a for instance, the Germans put alot of their ship production in WWII into producing the Bismarck and the Turpitz to the detriment of other more useful, smaller ships, despite the fact that they had a smaller navy than the British. The ships were so prized that neither saw alot of action (I think), yet their destruction were major blows in terms of morale and the relative waste of economic production that led to their construction.
It may not be the best analogy, but it is at least illustrative of my point.
On this past server, killing a BB would only have been worth 8 VC points, and another one could have been easily built. Had anyone actually accomplished taking out the B10, it certainly would have been a hell of alot more difficult than taking out some base hex of an equivalent VC value. This is also a basis for valuating VC points: how hard is something going to be to do. Certainly, taking core worlds is harder than taking out border stations, but taking out a valuable capital ship piloted by an experienced captain is also a major undertaking. Let's value that effort in similar manner to map-based VCs.