Let's compare:
Wisconsin 2008: Obama +13.9
Wisconsin 2012: Obama +6.9
2012 National Swing: Romney +3.3
If Wisconsin only swung with the nation, it would have been Obama +10.6. Clearly, Paul Ryan was a significant help, but not significant enough to make Romney actually win the state. On the other hand:
North Carolina 2000: Bush +12.8
North Carolina 2004: Bush +12.4
2004 National Swing: Bush +2.9
So, Edwards kept NC from swinging with the nation, and even narrowed the margin a bit from 2000, but the overall effect was far less than Ryan in WI.
Let's look at another: Sarah Palin
Alaska 2004: Bush +25.6
Alaska 2008: Bush +21.5
2008 National Swing: Obama +9.6
So, Alaska swings, but nearly as much as the nation did. Palin definitely helped.
And to close this off, let's look at Cheney. 1996 was crazy (Perot), so let's compare the Wyoming margins of the 21st century:
Wyoming 2000: Bush +40.1
Wyoming 2004: Bush +39.8
Wyoming 2008: McCain +32.2
Wyoming 2012: Romney +40.8
So, it looks like Cheney's effect in Wyoming wasn't much - Romney achieved an even bigger margin, and 2008 can be explained by that year's national swing. But to answer the question in the poll, Ryan definitely wins over Edwards.
But Michigan swung by pretty much the same margin as Wisconsin did, so it isn't a perfect comparison.