A two-party system, where both parties are roughly evenly balanced, leads to increasing polarisation as each party seeks to distinguish itself from its rival. This, in turn, means that a potentially large proportion of the electorate, the voters who vote for the losing party, become disenfranchised, because the policies of the winning party will not reflect their views.
Firstly, the notion that either the British Labour-Conservative "polarisation" or the American Democrat-Republican likewise exists is a great fallacy.
They are hardly polarised at all. Like two people who loathe each other but who are very alike, they use words to try to deny their similarities. But the fact remains: they are alike.
In Britain, the last 30 years or so have been characterised by all three main parties chasing exactly the same voter group: "Middle England", "Little England", "South East Man" or "Mondeo Man". Take your pick. Either pseudo or lower middle class, he/she are characterised by high personal debt and a largely mistaken belief that they've moved up a notch or two on the social ladder. Being "Aspirational" doesn't mean "I've made it!".
BOTH Tories and Labour have: supported American wars, continued with privatisation, redistributed wealth upwards, encouraged and de-regulated the City of London, spread the notions of PC and Multiculturalism (despite their denials), and really, there's little to separate them if you view (a) their actions and (b) their results instead of what they said
they were going to do.
I agree that people see it that way, (that there is a difference), but the British public are not known for heavyweight thinking.
Don't forget, also, that the time for consensus politics may come again, but not now. Thanks to the British media and those damned cameras in Parliament, British political leaders HAVE to be "strong" in the "elected dictator" style popularised by Thatcher, as opposed to the more consensus based rule of Heath. The stupid public wants
docile, amoral and deeply undemocratic Government, which obeys the wishes of the fuhrer, sorry, leader.
The government you suggest (a) would be a major improvement
in my eyes, but would lead to visibly weak, consensus based politics, which is how democracy is supposed to work. And (b) such government was the norm before the 20th century and especially before Thatcher and everyone since. Sure, they aligned themselves with certain parties, but there were so many subdivisions that an 18th or 19th century politician could be referred to as a "whiggish Waverer" even if he was a Tory!
Unfortunately, the rise in Independent candidates is a red herring, as almost all are closet Tories or at least "Wets". But an encouraging sign would
be the rise of smaller, new parties. It would be if too many of them were not of the extreme right, anyhow.
I agree with your idea: I just don't think the sheeple will support it. Yet.