Agreed, if anyone dies (aside from two players), they lose, and three will likely die NP1. How can you judge motivations when you know everyone's motivation is to stay alive? I'm thinking town should have a vig, since apathy in the DP is likely to ensue. Further, when 2/3 are third party, most players will lose the game.
FYI, mharman, the SK should not win until they are the last one alive. This will motivate survivors to find and lynch the SK.