Romney will represent decorum, politeness and everything good about America and the media will contrast his behavior with Trump's supposed crudeness and base behavior.
But like McCain, the media will use him when they need him and ignore him when it is inconvenient. Romney will be clueless.
Mitt will be sadly disappointed if he wins and then realizes be is completely irrelevant as there are now over 55 republican senators including blackman, r. Scott, etc.. that will make his vote and voice meaningless.