The problem with the combination of FPTP and the two-party system is that you can't vote for your real preference, you have to opt for the less worse of two package deals. However the winning party will then claim a mandate for the whole package, warts and all.

Looking back though, it has long seemed to me that whenever we had a change of government either way, then invariably:
    - the incoming party had to spend the first two years or so fixing the other lot's mistakes,
    - the next couple of years were spent introducing their own common-sense reforms, generally welcomed,
    - after that, policy tended to become increasingly driven by party dogma, until eventually the electorate were pushed too far and voted them out again.

So there is some sort of long-term balance, I suppose.