Thanks for hosting, Bob; your games are always enjoyable to read/play. And congrats to my fellow townies and to def and TP! Good job, guys. I'm glad youdidn't let me down. I'd have certainly been disappointed if my martyrdom was for nothing.
Like def said, adding third parties who can complete their objectives before the game is over upsets the balance. Once someone's won the game, they have no reason to continue playing, so they'll either A. ask to be modkilled/just stop playing (thus upsetting the balance of players) or B. tip the scales for one faction or another, again ruining the game's balance. Even if they have another win con, it's important to make them play the entire game just as town and scum do (such as def did in BB1 when he made Sandy kill 3 people and survive to end)
In addition, it's important to make sure you don't have any neutrals that can cooperate with town; the way the game is played now basically invites any neutrals to townside and thus make the game even more stacked against the scum than it already is with the current playerbase.
Anyways, all in all a good job! Very enjoyable game!