If they go full sandbox, it will be up to us, players, to set up our own objectives. No story to guide us, or just the bare minimum to introduce the world(s). As @Finland said, these objectives could be aligned with some themes such as discovery, conquest, knowledge, and so on.
They talked about ‘inhabitable areas’ at the end of their post, which could mean that players could create their own town, which would mean in turn that settling and pioneering are a possibility. If resource management is included, settlements could have more strategic consequences on the region - allowing control, bonuses and whatnot- and maybe environmental ones too. Then, the conquest aspect would be interesting because players would be able to size the hard work of the settlers for their own. Factions would then battle to control buildings, resources and regions.
If there is a story, the only clues I had would relate it either :
—With the race background: Conquest for demons – resources are rare on their planet apparently – , cooperation against natural dangers for beastkins and effort not to anger the almighty nature, and… I don’t have real ideas for humans. A mix of it all with a touch of trade?
—Or with the fact that the planets are linked and how the races interact, leading to a global story with world bosses or huge events changing the environment permanently.
