So it's if your initial stab downwards hits just right, rather than if you land on someone while the sword is still pointed down?
It sounds like it. I mean, what Sakurai said is true. This could make Link incredibly powerful, because unlike TOON LINK, he doesn't die if he does it. Plus, it's right at the beginning of the smash. However, the downside from this is that it might completely change the power of the initial smash and force people like Lou to completely change the way Link is played. It will all depend on if the smash keeps its original power.
It could also mean that they give Link's other smashes some actual power.