I would be interested in seeing this question moved to one of the discussion forums, as I am (unfortunately) certain there would be much discussion in response to the rise in the amount of bullying that seems to be occurring in too many schools.
Any reader who has ever entered a new situation on his/her own can identify with at least some of the emotions and experiences described in the book. That part of the story is universal - even the most out-going individual has experienced butterflies in the stomach when starting in a new place with strangers.
Junior's life is complicated by all the ramifications brought on by the circumstances of his change in schools. As our society becomes more mobile, as more families splinter and go in different directions, as we become more ethnically diverse, there are going to be an increasing number of opportunities for bullies to take advantage of kids like Junior.