As you've considered, compulsory voting on its own doesn't solve the problem of disenfranchised voters. In Australia, I believe that they have compulsory voting

As you've considered, compulsory voting on its own doesn't solve the problem of disenfranchised voters. In Australia, I believe that they have compulsory voting and preference voting. So, people who are forced to vote will choose candidates in the order that they appear on identically printed paper ballots. This leads to the derisory comment that a politician listed at the top may have obtained office with a "donkey vote". It has also led to the election of dead candidates. I believe that compulsory voting with a "none of the above" choice does exist. I'd be in favour of wider adoption. However, politicians have little incentive to change a system which was favourable to them and voters would rather see more important issues being tackled.