I am kinda lazy now, it's time for my skincare routine lol. But this is Yuzuru when his Flip was still meh, this was at JWC 2010, he got flat ! call for it): http://imgur.com/6CdF0gd
You see his outside edge? And even if you do not look at his edge, you see his left leg was not straightened, this was when he's 15.
And look at the close-up here in 2017: http://imgur.com/7FfH7cK
You see at the take-off, his left leg was straightened a bit right at the take-off. That's the improvement. That straight leg even just for a half second means it's a Flip. Yuzuru does not have to be scared of his Flip edge now.
One more thing, Yuzuru has NO pre-rotation in the Flip and Lutz, that's why it's possible for him to correct the edge in the Flip. Blade of Passion often complains that Yuzuru makes his Lutz too hard because he has ZERO pre-rotation. But actually, it's this Zero pre-rotation helps him to get ok Flip now. He pulls himself up too quick before the Flip slight inside edge can rock to the outside.
Wowww. Thanks for explaining.