Top three most underwhelming
Smoothie - terrible, non-existing, feats for a YC2. Make Perospero the great YC2 instead, he is cunning, decently strong and has only been struggling against Pedro the terrorist and Sulong Neko.
Snack - a gloomy punch bag. Perhaps Big Memes fault promoting poor young Snack to early in his career, this setback might take a toll on his psyche and he might never reach the hights he should have.
Queen - terrible feats for a YC2, plays around without getting anything done. Getting slapped around by Chopper, inadvertently turning Hyogoro back to his prime, not getting rid of X Drake, not drowning Big Mom, playing with Sanji until it was to late...
Jack, Jozu and Cracker tried their best, just got beat by stronger characters such as sulong minks, admirals and future yonko.
King, Marco, Ace and Katakuri delivered. Just got beat by future WSS, future fleet admiral and future yonko.