School reform is a very broad term that could encompass a number of different things. Therefore, the specific significance of school reform is hard to identify. Overall, the significance of school reform is that it could, if fully implemented, radically change the school environment. This is true of many proposed reforms.
For example, the No Child Left Behind law is one attempt to reform schools. This has changed the way in which schools work because it has caused schools to have to focus much more on testing and on the drilling the concepts that are on the tests. It has, in many cases, reduced the amount of non-core subjects that are offered.
Another example of school reform is the move toward things like merit pay for teachers and making it easier for teachers to be fired if they are not doing well. Depending on how it is done, this too can make teachers focus much more on getting their students’ test scores up.
Finally, there are proposals for things like all-year school. Once again, this sort of reform would completely shake up the way that things have always been done.
Overall, then, the significance of school reform is that it would, for better or worse, force teachers and other school staff to adjust to a new way of doing things.