Interesting analysis. The only drawback is the strategic voter, common in FPTP elections.

A vote cast towards an unlikely winner is almost as good as a vote cast for the worst of two evils. Better to have the least of two evils than the worst. Right?

I sometimes wonder why a prominent Republican does not run as an independent, just to siphon off votes from the Republican side, giving the Democrats a victory. Trouble is that voters thinking of voting for this "independent" would no longer be casting a vote for the Democrats. It's so hard to predict where the votes are going to go.