Your question is one that has been debated for some time, and almost everyone you ask will give you a varying degree of what they feel is an appropriate amount of school rule.
Because of the increase in violence in schools over the last few years, unfortunately schools have been forced into more invasive forms of keeping students safe such as backpack checks and metal detectors at school entrances. Due to an increase in negative and disruptive behaviors by students some teachers have had to adopt more of a zero tolerance policy when it comes to individual discipline in the classroom.
Has your child experienced something that they feel is unfair? Do you feel that your child has been unfairly punished in the classroom? If this is the case, I would not hesitate to take your concerns to the principal to discuss specifics.
There continues to be a debate as to what is appropriate classroom discipline and how much discretion individual teachers should have. An interesting topic to keep and eye on!
I think school rules are important for protecting the health, safety, and rights of everyone in the school. How much is too much or too little, seems best determined on a case-by-case basis with each school and its particular situation and needs. While some rules are mandated by law, others are optional, so I think it's really up to the school leadership and school community to determine what works and doesn't work with their school's set of rules.
Also, this topic appears to be commonly-debated. For instance, when I googled, "how many school rules are too many?", I found many blogs, discussion boards and newspapers exploring the question, with numerous opinions shared. Here's a related article that might offer some insight for you: http://www.eduguide.org/Parents-Articles/Discipline-in-School-646.aspx
On Education.com, I would recommend you visit the Positive Discipline section, where you'll find a variety of rule-related articles. Though many are targeted at parenting, I believe there is also some wisdom here that can be applied to rules at schools as well. http://www.education.com/topic/positive-discipline/
Thanks for your question! I hope it sparks others to chime in with their thoughts on the matter too.