Searing does not hold in the juices as once thought, but it can add some nice, deep caramelized flavor, so I usually do it.

Additionally, most "roasting" recipes aren't really roasting, they're baking, so the temps aren't hot enough to give you that caramelization. "Roasting" needs to be at least around 450 degrees or more with some fat, which will caramelize for you.