That's a VERY interesting mechanic change. Ledge invincibility shenanigans could become completely different... but the question is, in what way. I want to assume less time in the air means more invincibility frames, but who knows. Assumin' Sakurai would implement the seemingly sensible option is moot. Y'know, tripping 'n all.
Not having a slow get-up attack/roll at 100%+ may also be a blatant advantage for heavier characters. Surviving longer was only so much of a boon if ya had to grab the ledge to survive every time as said heavy characters.
And I really want to know what's goin' on in the pic of the day. If someone lacks invincibility frames, can you grab the ledge from them? Is it automatic? Or do you only do it if ya have lower percentage or somethin'? This could alter the off-stage game completely... and possibly give characters with shitty recovery some hope. Or just make edgeguarding even more difficult than it is in Brawl, which may make me want t' murder Sakurai more than tripping did.
... ... ... Or maybe Link just sweetspotted Up-B and hit Mario at the same time.