The top/bottom of the ballot thing is rubbish. Basically each senator is aligned with a political party, if a party has 2 or more candidates in the running for senator (I think?) then they get an "above the line" box. And if you desire, you can tick the above the line box to let that party place your vote for you.
So what ends up happening is instead of a diversified senate with plenty of conflicting opinions and a broad knowledge base acting as the gatekeepers of whatever ridiculous legislation the lower house can dream up, we end up with the two major parties controlling the whole senate.
And whenever that's not the case (which sometimes happens due to the preferential voting) the media runs a huge billion dollar campaign about how the entire country is going to stagnate into a giant flaming pile of shit unless one of the major parties gets a majority in the senate and is allowed to push all their horseshit through unopposed. Then next election the uneducated masses vote against their best interests in droves once again.
The system is fucked. I don't see an easy solution, it's not like forcing below the line voting would be any better because then all the braindead racist bigots like Pauline Hanson would be voted in in a landslide due to sheer media coverage and we'd lose any lesser named senators that managed to grab an infinitesimal piece of power by aligning themselves with a major party.
Maybe if someone has a good solution they could enlighten me, I'd love to hear it.
EDIT: I should mention, if you elect to vote below the line you have to literally number every senate candidate, which is generally 50-100 boxes. The system itself is imposing a huge barrier to the average person placing an educated vote.