If you're KOing someone off the top and you're unable to recover, you should just accept that you're taking a 3/4 risk of losing the match to it.I have no problem with the Star KO not KOing people instantly, but, I greatly dislike how there's two different lengths of time before the KO registers.
I think that it should either always be the "fly off into the distance" animation or the "bounce off the screen" animation. There's no reason that luck should be a factor there. I've seen games of Smash decided by that before.
In other words, no johns. This is the kind of thing you can totally prepare for, and if you lose to it (and I can't stress this enough), it's your own fault. Because it's something you can prepare for, and it doesn't particularly break the game in any way, it's just aesthetic, and it's a neat aesthetic that should absolutely remain in the game.