Romney will move forward as every new President does. If he digs up the dirt, the same will be done to the departing Republican administration the next time the Dems take power. It is the way of Washington.
Plus, consider the fact Romney has a number of complicated and politically polarizing issues to deal with that will consume considerable political capital and the goodwill of the people. Rolling back Obamacare, tax reform, and spending cuts will be fought by the media and te Democrats. He will have e big enough fight without also dealing with the potential the American people will perceive him as mean spirited for investigating and prosecuting Obama administration officials.
Then the corruption will continue unabated and Romney another puppet.