It's what makes the character believable. The fact that if you pound on Shepard long and hard enough, he/she's bound to break at some point. And even if he/she stands back up to face the drums of destiny, it would never be as before. Event forever change you and defeats... well, they forever mark you.
There was also being near death in a coma for two years - that too changed Shepard though coming back and fighting for the lives of all in the face of some ancient design well that too.
Each and every even etched deeply - so yes the doubts make the Shepard human.
Each and every even etched deeply - so yes the doubts make the Shepard human.