I think your last point is probably more the reason for France's strong showing in juniors than ROG (although that's just my opinion). The FFT have had an excellent system of coach education and certification for many, many years. The quality if their coaches is very high, and as you say they have a uniform approach (as do Spain, Argentina and many of the former Russian states - maybe there's something in that, and they don't or haven't until now used ROG).
Constructive use of the equipment will help. Mandatory age grouping of players with equipment for competition may not!
On the flip side (throwing a potential spanner in!) at Let Petit AS last week you had all four boys SF's and one of the girls finalists! They didn't grow up on ROG competition (probably). Just goes to show there is not one 'right' approach!