If we all agree that one party states are bad, why are two party states not almost as bad? (when compared with N party states, for N>>2)
(in particular, an N party state gives more incentive for each of the parties to be for something, rather than degenerating to "against the other")
The rise in alternative voting methods I think is because people really want a third-party to do well but if we have A,B,C and you prefer C > A > B but A,B are most likely to win in a first-past-the-post scenario then by voting for C you're indirectly helping B (you're least favorite) win as opposed to voting for A where you're helping your second favorite.