The Worst Generation refers to the 11 Supernova members who arrived on Sabaody Archipelago two years prior to the current events of the story when the Paramount Water took place, along with the addition of Blackbeard.
These characters have become key to the new era of the One Piece world and have established themselves as major figures in the New World. While all the members of the Worst Generation are incredibly skilled, there are some who have, so far, disappointed the fans by their lack of decent showings.
5 Basil Hawkins
The Captain of the Hawkins Pirates, Basil Hawkins hails from the North Blue. He has a bounty of 320 million berries on his head and, until recently, worked under Yonko Kaido. Hawkins is the user of the Wara Wara no Mi, which is quite an incredible Paramecia type of Devil Fruit as it allows him to control straws at will.
Added to that is the fact that he can use his tarot cards in conjunction with his Devil Fruit. While Hawkins certainly does possess quite a lot of potential, his showing in One Piece's Wano Country arc was less than impressive. After his defeat to Killer, Hawkins looks to be on the brink of death and might even have died already. If he does survive, he might get another chance to impress the fans in the future.
4 Jewelry Bonney
A famous pirate from the South Blue, Jewelry Bonney is quite an intriguing member of the Worst Generation. Although she just has a bounty of 150 million berries on her head right now, much about her remains unknown post-timeskip. She possesses an unnamed Paramecia type of Devil Fruit which allows her to manipulate the ages of anyone she touches at will, including herself.
Bonney has some kind of history with the Celestial Dragons and, so far, very little has been revealed about her true goal and intentions. Unsurprisingly, Bonney has been disappointing so far, however, that is not to say that she won't shine in the future. In the final saga of One Piece, it's quite likely that Jewelry Bonney will get her chance to impress.
3 Scratchmen Apoo
The captain of the On-Air Pirates, Scratchmen Apoo is a pirate worth 350 million berries. After the two-year timeskip, he joined hands with Yonko Kaido and served as his lackey. Apoo possesses an unnamed Paramecia type of Devil Fruit that allows him to control sound and attack using what he calls "Fighting Music."
While he certainly does possess quite an interesting Devil Fruit, he doesn't have what it takes to be considered among the strongest members of the Worst Generation. In the Wano Country arc, he proved himself to be quite a coward and he doesn't have the spirit to conquer the New World. Apoo is quite a disappointment for someone with an interesting Devil Fruit. That said, his role in the story remains quite important as he is still alive and will likely team up with some other Emperor of the Sea.
2 X Drake
Hailing from the North Blue, X Drake is a former Rear Admiral of the Marines and during the Sabaody Archipelago arc, he was said to be a member of the 11 Supernova. Following the two-year timeskip, Drake was revealed to have allied with the Beasts Pirates. In time, he rose to the position of Tobi Roppo and has since then made quite a reputation for himself.
Despite that, in the Wano Country arc, Drake was, more or less, a disappointment to the fans. He was overpowered in almost every fight that he fought and his showing was far below what one would expect from a member of the Worst Generation. What's interesting, however, is the fact that he is actually a member of the secret Navy unit called SWORD. In the future, Drake will certainly have a more pronounced role in the series and will more than likely make quite an impression. For now, however, he remains to be a disappointment to the fans.
1 Urouge
Hailing from the Sky Island of Birka, Urouge is the Captain of the Mad Monk Pirates. Prior to the timeskip, he had the lowest bounty of any Worst Generation member at 108 million berries. After the timeskip, Urouge seems to have done well for himself as he's taken down one of the Sweet Commanders of the Big Mom Pirates, named Snack, who is worth 600 million berries.
Despite that, Urouge's involvement in the plot has been negligible so far. As such, his character has been, more or less, a disappointment. That's not to say that Urouge's role won't improve in the future, as he certainly does carry a lot of potential. For now, he is in desperate need of more screen-time and more characterization as fans know little to nothing about him.