There are enough issues that they could be even more spread out among parties. How many elections has Joe Schmo sat there and said "Well I agree with A that the Republican/Democrat candidates say but I hate that they think B?" Quite a bit, probably.
More parties means more choices. Instead of 2 homogenized bloated monsters, we can find more palatable groups.
I realize there's downsides, as well. But after the last 15 or so years of American politics as usual, I'd be ready to try something else. Wouldn't you?