First of all, I hear you are concerned about your child's level of stress. I would speak with the teacher or school counselor about your concerns. Fifth grade may be a milestone grade where passing a high stakes test will determine whether your child is promoted to the next grade. If your child is doing homework more than one hour an evening that may be a problem. Children need to have time to play and relax.
You are also concerned that your child is doing "too much" homework and not enough art. This does not mean that your child cannot be enriched by doing art at home or in a different setting. There may be after school sessions for art to tap into children's talents.