That's a pretty normal ratio man.We didn't have fewer targets, we had to kill the entire village. Whereas the village only had four possible targets, we had seven possible targets (village & new res.). With one kill per night, and only two people on the "kill all humans" team, I'd say we lost quite easily.
In a game of 16-17 people, you'd expect to have 4 wolves. That would be 12 kills for you and 4 kills for them. Like I said, the problem isn't really the sizes of the teams so much as the fact that the ratio of villagers/wolves is usually offset by the fact that the wolves can kill ANYONE and it works towards their victory.