I believe that this lesson is very appropriate for our generation. It is well known that we live at a time of abundant, perhaps unprecedented temptation. The emphasis on Yosef HaTzaddik resisting temptation because he saw his own image needs to be underscored.
In my experience I have found that focusing on the gravity of the sin is not an effective deterrent in our day and age. We need to emphasize the form of mussar that stresses the potential each person has, how much he or she can accomplish. It is not even enough to emphasize the potential of people in general; the stress must be on the individual and the great things that he or she can attain. This mussar, the mussar epitomized by Yosef HaTzaddik’s refusal to succumb to temptation, stands the greatest chance of success in our world.