#6 The books already paved the way.
We already know that BioShock translates well to other mediums, simply because the books have been great sellers and pretty good in their own right. BioShock: Rapture and BioShock Infinite: Mind in Revolt have been out for years, and the former is certainly the more successful of the two.
The reason for their success ties into the earlier point about how dense these games are. Going further, it has a lot to do with how well-conceived the universe and pathos of BioShock is, thanks in no small part to Levine and his team, who spent years working to make these settings and characters come alive.
If you’re worried about BioShock jumping to film, at least consider whether or not the project has a craftsman like Levine behind it who understands and appreciates what makes the games so compelling. The books weren’t written by Levine, but they capture the spirit of BioShock and try something new in order to expand the scope of the games, and that’s just one reason why they work.