Here's a few things that I think would incentivize kids to work on the mat:

Add the push out rule like Greco-Roman did. If you step out of bounds, the other guy scores. If you get pushed out, it doesn't mean you're stalling, it means a bigger or stronger guy is having his way with you. He should be rewarded for gaining and using an advantage.

If you hook both legs on top, you get about 10 seconds to turn the kid to his back. If you can't stale mate. A second time, stale mate. A third time, you're stalling.

If you take a side head lock from the rear and don't turn your opponent in 10 seconds, same rule.

The infinate holding with no intent to do anything is hard to watch.

Erik Hinckley