I think that some story of sorts would be a good idea, as there is a lot of potential to put one in the game, it probably should not be very heavy, but some story element would be nice.
Also some aggressive mobs and some way of having them so that they do not destroy your first base or are a problem in the early game, like having cave systems which are needed for game advancement, but have some sort of hostile enemy that the player can fight or avoid.
