National curriculum has probably evolved since you were at school, even if you left relatively recently there have still been more vocational subjects have been introduced into the curriculum. Research specific changes as they will be personal to you depending on when you left school. Schools also employ more technology in a greater range of subjects than it's likely you were used to. Behavior is unlikely, however, to be a bigger problem than in the past: yes, there are some poorly behaved children and there are always a small number of reported incidents in school. Remember though that classroom management is an important part of teacher training.