While coalitions are a legitimate parliamentary option, in the current coalition in Britain, the Conservatives already had a plurality, and therefore, based on that and the lack of precedent, I think it's fair to question the legitimacy of parties forming a coalition where no member party has a plurality of the vote. If a plurality of Canadians give a mandate to one party, I question the legitimacy of a "coalition of losers".
The fact of the matter is, in the UK a 'coalition of losers' (As you call it) was almost a possibility. After the election, there was a lot of time spent between the Liberal Democrats and everyone else, trying to figure out who they would side with to create a coalition government.
It was the unpopular Gordon Brown, and the scandals that were plaguing the Labour Party, that more or less tipped the scales in favour of the Lib-Dems siding with the Conservatives. After all, Labour's policies are closer to the Lib-Dems (Look at the upcoming May Electoral Reform referendum; Labour and Lib-Dems support it, Conservatives don't), but Labour was in dire straights and holding a broken reputation that would only harm the Lib-Dems in the long run.
So the idea that the Lib-Dems only sided with the Conservatives because they won the most seats, isn't exactly true.
And what about Saskatchewan?
In 1999, we had a governing party receive less of the popular vote (38.73%) than the opposition (39.61%); yet the governing party won more seats than the opposition party. We had:
29 NDP
25 Sask Party
4 Liberals
Yet, despite having more seats, the NDP formed a coalition government with the Liberals who were elected.
That is a scenario Canadians should consider; even though the NDP could have taken the Clark/Harper route, and attempted to govern without the aid of the opposition, they reached across the house and found ways to compromise and agree with the opposition.
Harper's never done this, and frankly, he should have. Instead, Harper's been a bully in parliament since he was elected. It doesn't help that the Liberals had a successful surgery to remove their backbone back in 2006 either.
A coalition is what Canadians, and even Harper, have talked about: Parliament coming together to work with one another. And yet, people seem to forget that Harper has run rough-shod over Parliament as much as he possible could; taking the 'my way or an election' stand so many times I've lost count.
So, him saying he wants Parliament to work is hypocritical; given that his definition of making Parliament work is for the other parties to bend to his will unquestioningly.
And I don't recall if we've had an electoral reform argument here before, though I do agree something needs to be done. First past the post is a system that no longer works...
But mixed-member constituencies and party list systems aren't much better.
Personally, I favour instant run-off/alternative vote (1, 2, 3, 4 choice voting) based on a simple 51% quota...
But that's a conversation for another thread.