Wait, Arwon, you want to weaken parties while introducing proportional representation? Which inherently increases party strength (and required discipline).
Labor and Liberal members of parliament virtually never break ranks in parliamentary divisions. Yeah, it sucks that Labor punishes violating caucus solidarity with expulsion, but that's a feature of how it has operated for 100 years. Likewise the Liberals tend to have their own methods of punishing people who go against the party line, too.
I'm actually pretty agnostic on the level of party discipline in Australia, but it's a distinctive feature of Australian politics to be commented on as compared to, say, the US or UK.
It mainly becomes an factor on wedge issues, and it's a topical issue at the moment because both major parties are pretty hopelessly split on a number of progressive issues like gay rights, refugees and climate change (with the conservative tendency dominating in both Labor and the Coalition). I suspect this is why Camikaze mentions it.
However, to the thrust of your point, I favour Hare-Clark with
Robson rotation like used in the ACT and Tasmania. Multiple ballots are printed with random candidate orders, and there's no "party" or "ticket" vote box. People therefore still must vote for individual members.
It ensures a healthy degree of turnover, removes the choice of candidate order from party machines, is a way for unpopular sitting members to be replaced, and functions as an incentive for individual members to distinguish themselves and build a personal following. It works, too. In Tasmania's most recent election, some Labor candidates were ousted by
other Labor candidates among the 2 of 5 seats they won in each electorate.
Babbler: There is, supposedly, rigorous
internal debate within the Labor Party caucus, but once an issue is decided and a vote taken, all MPs are bound by that policy in public statements and parliamentary votes. I think you're reading "party discipline" as describing the internal mechanisms of the parties, rather than referring to solidarity in their outward behaviour, which is how we are using the term.