[Comet]

They haven't talked much about this aspect of the game yet but Higby has stated numerous times how taking territory can be a viable strategy for starving your opponent of resources and/or certain vehicles.

He has only mentioned the Galaxy so far as being from a tech plant but I would not be surprised in the least if there's more vehicles on that special list that need certain bases to spawn.

Otherwise, they'll have to solve the issue you mentioned (why take a lightning when you can take a vanguard?) solely through resources and cool downs. Which is entirely possible as well.

We'll have to see how it plays out come beta.