The concept of risk may have been overlooked in the mortgage marketplace over the last few years, but things are changing. And it may not be a bad thing, according to Tom Lund, executive vice president of single-family mortgage business at Fannie Mae. During a recent Morgan Stanley conference, Lund noted a number of changes Fannie has seen emerge in the mortgage marketplace of late. “We’re seeing a drop-off in home sales, and we’re seeing…