Why Romney would be a disaster in a nutshell: "Mitt Romney chose to unveil the economic plank of his campaign for the Republican nomination with a speech in Aurora, Colorado decrying banking regulation." Read the whole thing.
It's not that he learned nothing: he has chosen sides.
At the onset of the crisis, Romney was calling for end to mark-to-market valuation of assets, a clear sign that he was of the banksters, by the banksters (banksters wish to value their assets at prices that they are free to contrive - it makes the balance sheet so much prettier).