If the purpose of school is more than the transference of curriculum, then assessment must be more than numbers.  The very idea of genuine learning contains the growth of the individual learner as a central goal, and it raises the very real question of how to assess personal growth.  Certainly, it will be much harder to come up with a quantifiable result - we humans are much too complex for that blunt of a symbol - so another approach must be taken.

What is needed is a broader definition of communication over successes and challenges, preferably dialogues between the teacher and students and the teacher and parents.  Grades can serve a valuable function as a springboard for those conversations.  They become a means to an end, which is their appropriate role.

As in any dialogue, the nature, even the subject of the conversation depends on the needs of the people who are conversing.  This is true of a teacher-student conversation as well as a teacher-parent conversation.