This question stems from a conversation I overheard while in line at Starbucks, where a guy who voted Obama was thinking of voting Romney this time, not because he thinks Romney is necessarily better in theory, but because he was concerned that an Obama 2nd term = 4 more years of unproductive gridlock. He lamented that he wasnt convinced that Romney could bring the 2 sides together either, but we have years of proof that Obama cant. For him, it was the old "lesser of 2 evils" dilemma.
Of course it would be great if less divisive partisanship in congress gave way to co-operative productivity, whether that happens or not remains to be seen. The country is certainly more polarized now than it was when I was a young lad. I still think that a 1st term Romney who presumably wants to get re-elected in 4 years has more incentive to try and foster a more compromising approach, than a 2nd term Obama who knows this is his only remaining chance to implement his ideals, and he'll be moving out of the White House in 4 years no matter what.
I do have to say, that its interesting to hear "the US economy will mostly do whatever it does, based on factors beyond a president's control". I'm not sure how one could maintain that position while agreeing with folks who suggest that Obama inherited a bad economy which arose due to awful Bush policies. Can't have it both ways.