...and yes, I'll also confess to being a fanatic on that point
Despite my belief that political parties have to be tolerated in a democracy. I think political fundraising should be closely regulated to ensure transparency, and I certainly do not think parties should have any special privileges, such as constitutional recognition.
I really dislike the 1977 amendments. I think things worked out OK in 1975 - in the end - ideological succession deserves no protection. This just entrenches the exact problem most folks are identifying in this thread - the overly partisan nature of the parliament. The less effective parties are at protecting and electing their members, the less the members will feel bound to their parties. Less partisanship, not more, would have produced a much better result in 1975.
Political parties in the US are much less partisan, with moderates frequently crossing the floor on important votes. I think this is a result of keeping the Executive branch more clearly distinct from the legislature. There is not so much at stake when a vote fails to carry. The government can't fall, etc. I agree with your earlier point, freediver, that our system is in a sense more accountable, precisely because the executive is more vulnerable in the parliament. The trade-off is a more rigidly partisan parliament, which nullifies that advantage, and effectively stifles meaningful debate in the house. Polarisation has been increasing in the US congress in recent years, a phenomenon which has been of great interest to both major parties there.
I like the US model better overall, and think we should adopt the US constitution, pretty much intact as far as is possible, when we become a republic. That way we can make full use of the precedents and experience the US has accumulated while still retaining the ability to fine tune it to our needs later, if necessary.