Doffy is Oda's best written antagonist although not his most effective one. Probably the only antagonist in the series who can show a vulnerable side and appear scarier from it.
Arguably, Crocodile is Oda's most effective antagonist. Alabasta was a slow burn of many smaller arcs and Crocodile himself was the first hard wall Luffy ever ran into. Combined with his James Bond aesthetics, multi-layered plan to cause havoc in Alubarna and the fact Luffy lucked into beating him makes Crocodile such an iconic villain.
Kaido & Linlin aren't even good antagonists let alone better than Oda's best. Kaido's goals are nebulous and he just wants to make a massive war. At least with Doffy, he had a deep set grudge against the World Government and had a reason to pursue such an outcome. Kaido just wants it but doesn't seem like the type to want the fame, power or luxury that'd come with it. He's just a barbarian.
There's an appeal in that, but for the big bad set up from chapter 650~ until now, I'd hope for something deeper and for Kaido to have more of a personality. He's pretty one note.
Linlin's got some complexity but it feels like every new side we learn about her contradicts the previous. She's an obvious gag character and that shows in her own arc. I do like the fact she's got her own nation, her own concrete plans and is theoretically smarter than Kaido. But she has almost no presence and her own cartoonish failures keeps me from taking this character seriously.
So Doffy & Crocoboy are much better. I think Kaido & Linlin fall short of average for Oda whereas the other two are some of the better examples of antagonists
