That's the thing - bicameral parliaments are unnecessarily complicated.
+rest of long post
While I agree to some extent, the lack of a second or upper house of parliament means that the party that has the majority in the lower house can pass whatever legislation they like, for the most part. Example of this being Howard's WorkChoices a few years ago (also contributed to him losing the election), a ****ty piece of legislation that only got through because he had a double majority. Had the Senate functioned as it should (double majorities are generally rare), WorkChoices and other bad pieces of legislation wouldn't have gone through.
There's the argument that 'they're the party we elected into power, sure they should be allowed to do whatever they like within the confines of the law', but apart from complicating the process, the second parliamentary house is also there to keep the lower house of parliament accountable and actually perform the job of scrutinizing legislation and form at least semi-objective committees and such, two things that aren't necessarily well done in a house where one party has a (clear) majority.
Things like this can be mostly avoided if you have a set of supermajority rules for really important things and - ahem - if you have more than two parties.
Having more than two meaningful parties will make a situation where one party has more than half the votes extremely unlikely. It has happened only once in the history of Finnish Parliament - in 1916, when the Social Democratic Party of Finland secured 103 seats out of 200. Note that Finland was not even a sovereign country back then, but a Grand Duchy under Russian Empire.
One party majorities are very likely to happen with only two dominant parties.
When the number of dominant parties increases by even one, the odds of one of them scoring more than half the votes decreases dramatically. In case of Finland, there are four options by and large - the National Coalition Party, Centre Party, Social Democratic Party, and the rest (which includes minority parties like the Greens, Swedish People's Party, Christian Democratics and the populist party called "True Finns" which sadly seems to be gaining more and more support and seats lately). And considering how the parties co-operate to form governments and appoint positions in committees, even the smaller parties typically still have some influence.
Then the other thing is, if there would be (for example) 600 representatives that run the entire Legislature, how would you fairly elect them so that they both represent their electors and their geographic areas? A district having 49% Republicans, 48% Democrats, and 3% Left-leaning Independents would have 1 representative who only represents half their electors. What it seems to me should happen is that the Electoral College be disbanded and direct election be the method for electing the nation's president. That way, Reps support individual districts, Senators individual states, and the President the popular opinion.
If that was the case, Al Gore would have been elected in 2000 with a split House (221r-212d) & Senate (50r-50d).
Finnish presidents were chosen by an Electoral College until the 1994 elections, in which Martti Ahtisaari was elected the president on the second round in a direct election.
The problem of representatives having "split loyalties" depends on how many seats you have in the parliament, but a parliament's ability to function is inversely correlated with the number of seats in it.
There's also a possibility where each state elected a committee of representatives, and they would choose a spokesman from their midst who would be responsible of casting the votes on behalf of that group. For example, in a committee of nine representatives, you could have for example four Republicans and five Democrats, and the committee would have a number of votes to give; either so that each state's committee would have an equal amount of votes (like now), or so that the votes for each committee would be representative of their state's population.
The number of representatives selected for each committee would be up to the individual states; only one of them would appear in the senate and cast the votes as decided by the committee.
Of course, it would be an incredible hassle. However, in a country with a de facto two-party system, having two representatives of the state in the Senate has all likelyhood to be representative of the State's division - provided the division is close to 50% and both senators come from different parties. In a case where both senators come from the same party, the minority party's supporters are essentially unrepresented in the Senate. The committee system or whatever you want to call it would resolve that issue, at least to some extent.
But all this political talk is taking us further and further from the original topic. Not that I mind, it is the nature of conversations to diverge into new areas as they progress, just a remainder that originally we were talking about wikileaks and the related hactivist attacks against both wikileaks and against the financial services that stopped providing their services to wikileaks.
