I don't see how forcing people to vote would improve things. People are largely uneducated about the issues and candidates. Is it better to mix in a bunch of uninformed votes from people that don't want to know and don't care?
Ultimately the act of not voting is just as legitimate in a democracy as voting is.
Mandatory voting, when many people don't like any of the available candidates and are disillusioned by their government, seems like an authoritarian measure to reinforce party lines. Because at best you get people voting "no vote" on most issues and positions on which they're uninformed, and at worst you get people just voting down team, er, I mean, party lines, further dumbing down the political process.
By the way,
As much as Republicans gave the Democrats an ass-pounding tonight, you should feel good that the electorate IS moving left. Legalizing pot, raising minimum wage.... and not only that, but Republicans were hammering Dems on not practicing what they preach. In Oregon, for instance, Wehby went after Merkley for not paying women as much as men. Furthermore she's a pro-choice Republican. If Republicans start winning on a platform based on what Democrats preach but don't practice, then that seems like an overall good thing to me. Who gives a shit about the letter next to their name.