I've been thinking that "Sid the Science Kid" with its class size of 4 makes "Cailu" with a class size of 8 look bad. When in reality class sizes for pre-school are more often 18-20.
Then there is "Dino Dan" that we're watching lately. His class is 3 girls and 3 boys. This is fondly reminiscent to "Magic School Bus." Let's think, Ralphie, Carlos, Tim, Phoebe, Wanda, and DA. Oh, 3 boys and 3 girls again.
You obviously don't want to have a television show with lots of kids in a class. That would be too hard to keep track of. It would give kids the impression that school is not so much a place of magic and learning, as it is a place of getting lost in the crowd.
That said, G's 1st grade class is actually only 4 kids. It's great. I love it that he's going to have small class sizes with the same kids for the next 12 years.