OVERRATED:
1. Zoro (He is no 'GrandMaster', he has flaws like everyone else. Stop pushing him as an Gary-Sue which is just as bad).
2. Mihawk (I respect Mihawk and what he can do, but he honestly below Yonkos and Admirals. He won't beat them if your having trouble with YCs stopping you easily).
3. Pica (It's an body made of stone, not Diamonds. He can be easily find and break through to find him. Stop saying he can even deal with Yonkos and YCs easily as hell no he can't).
4. Rayleigh (I enjoy Rayleigh, but he wasn't that deeply up to the point he could beat WB or Yonkos in his Prime especially his age right now as well).
5. Jimbei (Got no feats whatsoever in post-timeskip to push him that above even Monster Trio. BM Feat don't count since she was slimmer and still wasn't hurt by his attack. You can't count that at all. Plus he kinda more at or past his prime since given his age and timeline, don't think he be THAT (Emphasizing) strong in crew hierarchy, but he still be a strong member).
UNDERRATED:
1. Smoker (IT'S TIME TO STOP (MEME) on the Smoker's downplay as I understand what happen to him in Punk Hazard hurt where to put him, but he still one of the top fighters in the series and from Oda, he looking to be the 'Garp' to Luffy's 'Roger' as both have very similar relationship like them in being 'frenemies'. Plus Stampede movie while non-canon on events, for Oda to push him as one of the top fighters to help Luffy defeat Bullet shows that Oda still sees him as a major threat in NW as much as the others. Doubt we seen last of Smoker and he be much stronger next time along being Top 5 strongest at EOS overall to be one of the few who can match Luffy).
2. Bonney (I get she hasn't done anything in 'besting' someone much on-screen, but feel Bonney is looked down a bit than needed as she still an force to be wreckon with especially she is apart of the WG for a reason. From what we got and seen so far, she is capable of stealing and probably beating members of Yonko Crew (BM's) to take their ship as her own and is able to get into Mariejois easily. She also able to get survived bouts with BB and Akainu and still lived to live the tail as well. I feel Oda is working something big for her given her 'mystery' and we will find about it much later).
3. Moria (I feel like Moria despite how he been shown, is actually much tougher and survivor than we think as who do you know would go in an big fight with Kaido and again come in to fight BB just for their crew who are both Yonkos. While he didn't win in bouts, he does have balls and can take much more than people credit him for. Just more so he gotten a bit 'lazy' on his fighting style on why he been having issues, but feel once he get more active as he is doing, he be a threat in his prime as he should be. We can't doubt the reason he become WG due to his power after all.
There more to him than meets the eye as we see him again as well able to clashed and escape with Doffy who couldn't finished the job despite being order to 'eliminate' him.).
4. Ivankov (While I don't think it's that much, I feel there are a few/some who doubt Ivankov on how strong he is. He is an very top member in Ivankov who is very close to Dragon to the point he knows he has a family and strong enough that even Kuma feared him (Might still in his human conscious somewhere despite the change) too. He is strongest of the commanders and possible Third-In-Command to RA since next HQ after BB's took their main base was on Ivankov's island. We also can't denied him able to combat Kuma who could easily take many people with his abilities (Strawhats included; Twice) yet Kuma couldn't to him and he was sent in the lowest and secret lvl of Impel Down with major bad figures in there.
He shouldn't be underestimate than we think as well his influence too like getting people like Crocodile to do his bidding by 'tiny' blackmail and fight off Magellan who he did lost too, but was able to damage him enough to make him bleed).
5. Smoothie (I know we heard other saying 'Smoothie is THICC and 'UsELeSs' given her portrayal in WCI, but again think some still underestimate her over that when for starters, they say why she was 'running away' when BM was anger? It's BM with powers to take your soul away. Why you all think Smoothie can do something to beat her or even delay her? Stop BSing about that. She shows her worth in able to subdue Reiju easily along causing trouble for Strawhats at Sea which many comment about her abilities not just that scene, but others on her for being an Sweet Commander.
Also others feel like she should have done something to King when he attack the ship, but honestly how do you protect yourself on an moving ship going upward and enemy who flies come and send flames to attack from high in the sky. It wasn't good environment for her to try to do something especially her powers make her increase in size. You think it's smart to grow huge on an unsteady balance at an waterfall to try to attack someone? Use your brains than saying 'She is UsELeSS' when the issue isn't because she is weak or anything. Oda even in SBS vouch on her being very strong fighter, but just certain circumstances to prevent that.
There not much she can do on situation and being an YC doesn't mean you can do anything face with an problem as your not always perfect as shown with Katakuri who couldn't stop some events happening despite him having FS. She is an SC/YC for reason and Oda got plans to show her like he said for later which be in Wano arc as they go into an huge war. Doubt that's all she has to offer in the end).