Hi Ian:
Yes, having an understanding about yourself is important. Your comment about weaknesses is important, too.
If an instructor is overly conscious about a deficiency of some sort, believe me, students will pick up on that.
Just as significant is when there may be a deficiency present and the instructor is not aware of it. That's bound to impact the student learning as well.
Willingness to build on strengths and openness to acknowledge and improve weaker areas really takes a commitment by the faculty member.
Regards, Barry