American Ninja Warrior is different; it's not like the original where if you pass the first stage you automatically go to the next, they have the top 15 getting to go on. So not only do you have to finish the course, you have to do it as fast as possible. You're right it used to be they'd send those that finished to Japan, but now it's kind of it's own thing.
I've watched the crap out of the Japanese version and from watching this version of ANW, the first course looks tougher in ANW. Some of the stuff in the ANW's first stage is usually not until at least the second stage in Japan.
I didn't realize what a delay from taping to airing it was. Wimbley said that was filmed back in February.