I am assuming she wants to spend more time grading these but there is none. Perhaps the portfolio assignment could have a deadline of one month before the hectic time of a school year. It also would have been nice to see an example of a portfolio from one of her Algebra classes. I only mention this because I teach Algebra. As I mentioned earlier I would encourage any teacher, especially the rookies, to read this article.
Portfolios are a great way to establish communication between a teacher and a student.
They also help students take pride in their work. Another characteristic of the portfolio is that it offers teachers an idea, as well as a tool to assess, whether or not students value mathematics. Being a rookie myself I find it difficult creating new and fun ways of assessing my students. The age of tests and quizzes is slowly loosing steam. Students need and want to be challenged in a way that brings out their individuality.