I have been reading this discussion with interest. When my son was a Bear, I definitely thought the Bear program was repetitive and also, "too much like school." He was also bored with the program.
Webelos I and II go much meatier and more interesting.
Baden-Powell Scouting (BPSA) has kids in grades 3-5 together as one group, and that grouping seems good to me. GSUSA has Brownies as girls in grads 2-3. I'd say being a troop leader, grade 3 (second year of Brownies) was where it really got fun.
I don't know why we all are pushing so hard to get little little children into