Wow. I still think I would like to give it a shot. I hate the gap thats between the American people. The country is in two sides. We arent Americans anymore
The same divide will exist with a multi-party system. The only difference you'll likely see is that American politics will become less decisive and more divided.
For example, in Canada, virtually every single party with the exception of the Conservatives is either left, or left-of-centre. The Conservatives are the only right-wing party. Well, right-of-centre.
The left wing is split up by 4 main parties (Liberals - Toronto area, NDP - Northern Ontario/Prairies, Bloc Quebecois - Quebec, and the Greens - nowhere in particular).
There is stronger support for the left wing than the right. But because the left wing is split and the right is not, the Conservatives can compete neck-and-neck with the Liberals.
Our politics involve coalitions and backstabbings and old white guys screaming at each other. Things don't really get done very quickly. I prefer the decisiveness of American politics, but I prefer the safeguards against corruption of a Canadian style of governance.
Alternatively, I would advance the notion of a no-party system. Candidates run independently and are chosen on their merits, not blind partisanship.
Edit: I don't know how familiar you are with Canadian politics, but one feature of the multi-party system is coalitions. Smaller parties with similar ideologies will band together and compromise on issues and put their collective power together to stand a chance at power. That's how it is supposed to work in principle, but in Canada, the opposite happens.
The big parties with the highest chances of winning form the coalitions and the fringe parties stay divided. In fact, sometimes they make roads to divide further. I believe the Communist-Marxist party split up into separate Communist and Marxist parties not too long ago. Which was pretty stupid of them, considering they only had a few thousand votes. They were already insignificant.
One of the big issues of contention is forming coalitions with the Bloc Quebecois - the Quebec separatist party. The Bloc gets roughly 10% support (all from Quebec). They'll never attain power, but they play a huge role in keeping governments in power and taking them out, as it suits them.