Does anyone know if the game follows a mostly linear story, or is it rather open ended with random events that sort of tie together the narrative?

As I understand it, you try to survive till the end of the war. While doing that you are free to explore different locations (but the same on every play through?), at which there will be randomized resources and different people.

But I image that while you might encounter different quests in different locations on each play through, the total number of quests will be finite.

EDIT: Anyway, I can't wait for the game to become available :-)

This game is randomized, from the characters you start with, to the locations available to you, to the random events that trigger.

I think some of the locations can have a fixed table of events though, but all in all, its a fresh experience and approach with who you start with.