This was the developer's explanation from Youtube: "Basically Vektor Essentials strips back a lot of the functionality to make an easier to use and faster loading instrument. It does contain some sounds from Vektor but also contains new sounds too. In essence it is designed to enable Nova to create a series of instruments. So Vol 2 is currently in development and will contain a brand new set of sounds, patches and sources."
That was last year, no idea if they're actually going to release more.