I honestly don't think there's much of anything left to tell in the nuBSG story. It's similar to the way I feel about Middle Earth, in that the stories are so intrinsically tied to the characters that once their arcs are complete, there's not much else there.
I mean it would be like a series or book dealing with Dorothy's (Wizard of Oz) life in high school or something. Completely anti-climactic and pointless. Her story is done. So are those of the BSG characters.
However, I would not be opposed to a glimpse into the situation of the colonials in general. Focusing on a minor character (like Hoshi, Seelix or Lampkin). That might work, since these characters don't really have thematic arcs (at least, not to nearly the same degree). There could be a wide range of stories (religion, social organization, ethics, etc.) told from what would be a new perspective for the most part, fleshing out characters who were previously only footnotes. If, as I suspect, such novels were written by people other than the regular BSG writing staff/RDM, such an arrangement would give them much more flexibility to have their own take on these characters.
But I am against messing with what I feel is a good thing. Anything else related to the main characters in anything other than a cursory way would be unnecessary.
Imagine Seelix starting a junta, though! That I would pay to see...uh...read.