We need a parlimentary system, but we need coalition government. Government where compromise is the basis of government
Compromise IS the basis of government in a Madisonian system which is what the US has. Checks and balances, filibusters, all that. It's hard for one side to get stuff done unilaterally. The appeal of a parliamentary system is precisely the fact that it removes the need for compromise once your in power. If you control the government then you control the government.
Personally I am all for parliamentary systems because I would rather have the side I not agree with own it's results then have constant divided government. For instance in the UK right now, I think that the Conservatives have adopted some very counter productive policies vis-a-vis the budget. However the Conservatives know that they will be held accountable for their policies. As a result, they have a very strong incentive to make their agenda work as well as possible. This is clearly good because even if one disagrees with the conservative policies, one should want those policies to be managed properly.
In the US on the other hand, the republicans won the last mid-year election. As a result, they have the ability to force the government to adopt austerity policies and block stimulative policies. I disagree with the republican policies. But the republicans don't own the results of these policies. We are stuck in permanent divided government where no one takes the blame. This is good if you want all policies to be watered down but it's bad for effective government.
By demanding that both sides compromise, you automatically award victory to whoever is the most stubborn and unreasonable.