We notice the buffer system a lot, particularly a friend who plays as DK who has died many a time to performing moves as he fell off the edge (for example, pressing shield as a hit that sends him off the edge comes out, so that he enters an airdodge as soon as he begins falling).
The character that suffers the MOST from the buffer system is Ike. When you're by and edge, shield, and mean to let go of your shield to punish the person with jabbing, because your shield was hit you slide off the edge and do a Nair instead, Ike's longest aerial when it isn't near the ground and you're not fastfalling it. It's instant death for Ike players and I've had it happen to me one too many times whenever I play Ike.
The second and third characters that suffer just about as much as Ike are Snake and DK. Snake's Nair and Fair in an Ike situation can occur (jab out of shield would equal Nair and Ftilt out of shield would equal Fair). Fortunately, he can make it back in most situations but, you can't deny it puts him in a horrible situation especially if you're up against someone who has a meteor or knows about Snake's gimp with his Up B. DK, while his Nair, Bair, and Uair wouldn't cause him death his Dair and Fair will.
Ever tried to do the cargo Dtoss gimp only to have your opponent get out as SOON AS you press Down and A? Like, a WHOLE second before you even do the Dtoss. Yeah, you're gonna do a Dair and you're gonna accidentally FF it or even if you don't FF it, you'll still die. A Fair death for DK isn't that common but, it can happen if you try to Ftilt out of the shield after your shield has been hit and you slide off. I haven't, however, seen a DK Fair after trying to do a cargo spike (Fthrow/Bthrow) of the cargo spike due to someone getting out. But, in most situations for me, it's when I try the Dtoss cargo gimp and my opponent gets out a whole second later and I Dair.
Putting the bufer system on 0 might not be a bad thing but, if it is, I'll go for three at minimum and five at maximum. I'd LOVE for DK's cargo Dtoss gimp not to cause me death if my opponent gets out a whole second before I press down and A.
These are my reasons for wanting it gone or lowered a ton.