The government committee on primary education is set to recommend a classroom size of 30 so that teachers can give extra attention to weaker students to help with their learning.
I strongly believe that smaller sizes are better for students. When the number of students decreases, teachers can allocate more time to cater to the individual learning needs of each pupil.
Students can try several instruments without feeling the pressure to master one. Hence, I believe it would be unwise to make it compulsory for primary students learn a musical instrument.