At 1:35 of the second round, Le attempted a judo technique against Smith and only succeeded in moving Smith around for a few seconds. Mauro Ranallo, in his infinite wisdom, referred to it as "almost a judo-type throw, almost looked like a, uh, maybe an attempt at an uchi mata," pronouncing those last words uncomfortably.
Nope. Nice try. But instead of just yelling at my TV, I thought I could diagram the throw Cung DID attempt—my personal favorite—the Harai Goshi. I've also included an example of the throw done correctly.
Now for a perfectly executed Harai Goshi in MMA, we go to Corey Devela vs. Joe Riggs (you can watch the fight-ending throw in action here.):
Sorry for the tiny type. You can view the larger jpeg here.
The reason Devela succeeds where Le did not is in the fourth frame. Devela's right leg is directly underneath him, and he is able to lift onto his toes, lift Riggs' hips a few inches, and separate Riggs from the ground. Devela is now able to violently spin Riggs in mid-air with very little effort.
If you ever want to see a great Harai in action, watch Nate Diaz. A big part of his game involves a very flashy and effective sequence in which he gives up his back standing, threatens with a kimura, then hits Harai Goshi. He does it all the time, to the point that Joe Stevenson built much of his victory over Diaz on countering this throw sequence.