I work at a daycare in a preschool age room and I am allowed to have 9 children to myself. for that age groupe it is completly resonable. in my "classroom" the philosophy is learning through play, the theory is that a child will learn all the important things they need to learn by interaction and play with other children and age/developmentally appropriate toys. We do not use computers or telivisoin to entertain them and all play is child and intrest directed.
I feel that this is a perfect way to learn and that all children need to have more time avalible to them for using their imagination and to just be a kid!!