After watching that, I am 100% sold on Mario Maker turning out to be awesome, hopefully there's a good system for ranking user created levels so that the best are easy to find, a huge supply of crazy levels like they played tonight would be awesome.
Overall, I think the Nintendo World Championships was better than I was expecting. The announcing was generally not particularly good and the way they broadcasted Splatoon made it difficult to tell what was going on but other than that it was good, I thought they had a good selection of games, mixing new and classic, and ending with wacky levels from Mario Maker that they had never seen before was a great way to end it.