Hmm,
Marth has fthrow spike on everyone at 0%, which you may consider a chaingrab, and can kill characters with poor vertical recoveries (i.e. spacies)
Pikachu can 0-death some of his extreme chain grab characters if he finishes it with a Quick-attack lock into upsmash (very very hard, ESAM isn't even consistent with it, but done properly is definitely killing you)
etc etc, I'm sure you're generalising, so i'm being nitpicky for no real reason
And characters for sure can play a gimp-centric game. Watch Mew2King in melee, he stays next to the ledge for an entire matches for a reason, even if he doesn't have a projectile to throw at you.
The notion of "you making mistakes" is always a bit awkward in competitive discussions, its generally assumed you shouldn't make mistakes unless what you're doing isn't a "real thing" ('gimmicks'). We don't know how the ledge will go properly yet. If they've removed sweet spotting the ledge (in terms of making it harder than brawl), even if you will grab onto it no matter what, well timed ledge drop attacks and on stage edgeguards will be very powerful.