I concur with the fact that kids just take many more reps tahn teens or adults. The younger they are, the more reps they need. Also, how you present th ematerial is imortant. While I try to break techniques down into doable chunks....soemtimes with really young kids, that doesn;t work. They struggle with connecting the chunks.
So, I find that sometimes I just have to let their natural ability to move take over. for example, with roundhouse kicks, I used to break it down to turn the front foot, lift the back leg, turn th ehips over ad extend the leg and so on. Aside from the balance issues, the kids don't get it.
I changed tyo putting a kicking shield in fron of them and telling them to pu tthe top of their foot on target. It took fewer reps to get the motion down, then I was able to spend more time smoothing over the nuances once the idea caught on. Turns out they call that whole-part-whole instruction (as opposed to the part-part-whole instruction I was doing).
Keep what you're doing simple and soemtimes letting the kids figure it out will make them catch on faster than guiding them step by step from the get-go.
Peace,
Erik