Like typical of many Gary Stu's/Mary Sue's:
- He has no flaws at least none that negatively affect him or the Strawhats in any meaningful way.
- He has quirks disguised as flaws, a cheap writing tactic used to give the appearance of having flaws. He has a terrible sense of direction yet somehow always ends up in the right place when needed, he's an alcoholic but it never impedes his judgement or impacts his fighting ability, he's a sleepyhead but is never ever caught off guard.
- He never has any self doubts or second thoughts regarding the predicaments he's in. And as such he is never emotionally challenged.
- He has few if any qualities/actions that make him look unflattering or unappealing unless it's for comedic purposes.
- He has little to no character development and has remained largely static as a character. (No more moments like "Nothing happened").
- He has very little characterization outside of fighting, and rarely interacts with the other Strawhats outside of it. Like when's the last time he even talked to, let alone have a meaningful conversation with Robin or Brook?
- He is the least fleshed out of all the Strawhats. We're literally almost near the end of Wano and Oda has spent more time on him fighting then having him interacting with his background, parentage, heritage, his relationship with Ryuma, the Shimotsuki or their culture. Zoro hasn't had much plot relevance to most arcs post timseskip but you'd expect him to be much more involved in at least Wano but it seems like he'll be leaving Wano with as much knowledge going out as he did coming in.
Zoro pre timsekip wasn't a perfect character by any means but he was still a compelling character with depth, flaws, character development and interesting relationships but the writing for him post timsekip has emphasized more on him being a cool, badass action figure focused on fighting than an actual well rounded character.
gone 
gone 
