Also compulsory voting would mean less freaking out about voter fraud via people physically visiting multiple polling locations to physically cast multiple votes, and without people shouting about that every time somebody mentions voter fraud, maybe we could do something about the fact that it's easier to hack an electronic voting machine than to hack an electronic slot machine.

I hear you've got instant-runoff voting, too. The US and possibly the world would be substantially less screwed if we had instant-runoff voting in the US, because anybody who voted Nader would almost certainly have put their second choice as Gore, not Bush, which would have guaranteed a Gore victory, and Gore would have pushed energy efficiency much harder and Gore wouldn't have felt the need to prove his dick's bigger than daddy's repeat the Iraq invasion of the first Bush era, so even with all else equal we'd be better off.