What is a feasible way to move away from plurality voting?

[LiberalLovinLug]

7. With two parties there's a natural inclination to divide down the middle

Proportional Representation of some form is probably the most advanced democratic voting system.

In the US you may have a hypothetical situation of 4 parties. For the sake of argument, Libertarian, Green, Democratic, and Republican. If seats were rewarded based on the percent of over all popular vote, people would feel freer to vote for a more compatible party for them. So you'd also increase voters turnout.

It would never be a given, but for the most part Democrats would work with the Greens (or Our Revolution) and Republicans would work with the Libertarians... If they needed a bill support.

There'd be actual negotiation and compromise. Groups would be forced to get along to come to a majority agreement