Linda is probably one of the most insightful characters in the drama.  Linda is one who fully understands the frailty of her husband.  She understands how tough it is for him, given the world in which he is competing as well as his own sensibility.  Linda is not a practitioner of "tough love" or one who brings the harshness of the world into her love and reverence for her husband.  She is not a doormat.  Rather, she possesses a quiet strength and reservoir for patience that makes her such a powerful figure.  Miller's inclusion of Linda's characterization reminds the audience how off Willy is in his assessment of what defines success.  Any human being who has a partner like Linda has already embodied success.  Linda is devoted to Willy, offering to essentially operate as his shelter from the storm.  When Linda is referred to as "more than she actually is," it is a stark contrast of how loyal and devoted she is to her husband and ensuring that her love for and of him is one that provides a potential avenue for redemption.  Even if he fails to recognize it, Miller's characterization of Linda's loving treatment of Willy demands that the audience understand that Willy really was "something" for having a partner in his life like Linda.