Its really hard to make comparisons when the point cost is still up in the air.
That being said...
The speed 3 alone (even though it looks to me to be without a 2 yaw which could be easily remedied with nav tokens) is more than enough to put the ISD way over the top. The extra firepower, the better durability, the 5 squadron value, and the insane ability to shrug off crit cards are just bonuses.
I believe the VSD will go the way of the dodo unless they come out with an "Imperial Grand Admirals pack" (Armada's version of the Aces for X-Wing) where they have some insane upgrades greatly increasing the VSDs viability
(This is all purely speculation meant only to perk the imagination)