I'd like to give PR a try, though I don't expect it to be the end of the two-party system. Minority parties tend to be subsumed into one of the two leading parties, because any vote on legislation ends up dividing people into "yes" and "no" camps. Ideally, the coalitions would differ from vote to vote, but since the best way to get to "yes" on some issue is to trade off a vote on another issue, the coalitions tend to be fairly stable over time.
The advantage of PR, in the United States, is that increasingly people are voting for party over personality anyway. Personality tends to serve mostly as a liability: if you end up calling attention to yourself it's usually for something you screwed up. In a safe seat (as so many are), a distinctive personality will help you keep winning the primary, but in competitive seats the names you remember are largely the ones who committed some terrible "gaffe" (often manufactured or blown out of proportion by the press and the opposition party).
Once elected, they tend to vote the party line. If they do anything distinctive, it's most often just grandstanding, with little effect on the legislative outcome. A good politician actually can do some real wheeling and dealing behind the scenes, getting a favorable position for their district, but the effects are usually hard to see. The most prominent things they do are to vote the same way as anybody else would with the same letter after their name.
So since we're voting for parties over personalities anyway, we might as well give PR a try. Don't expect it to cure the ills you expect it to, since what we end up with is going to look a lot like a two-party system anyway, but it will at least allow us to reconsider the system. It might even end the practice of voting against whichever politician is most easily tagged with negative personality traits, so that they can focus on the party most in line with their ideology. (I'm not crazy about that, either, but at least it's slightly more real.)