The 30-year fixed-rate mortgage is due for an overhaul, according to a proposal published by the Federal Reserve. Members of the Fed’s research staff suggest that banks should offer a type of mortgage with no downpayment requirements that essentially automatically refinances. Wayne Passmore, senior adviser in the Fed’s division of research and statistics, and Alexander von Hafften, a senior research assistant in the division, authored a working paper published by the Fed last week. Passmore and von Hafften cited...