I think giving the VR two different SBs would be the best way to fix the VR. One would be the classic vasari SB, the other would be the new SB that would be unlocked after researching starbase mobilization.
This is how the new SB will be different.
1 -It will have the same design but it would be smaller.
2 -Because of its ability to jump it will only be able to have 6 upgrades.
3 -Because it is smaller it will have fewer weapon banks.
4 -It will have a lot less health and shield points.
5-Enemy ships jumping from the new SB will not lose AM or health.
I think this is the best way to balance VR without removing starbase mobilization.