Let's see Kaido was defeated seven times and captured eighteen times, was almost defeated by Oden. Shanks lost an arm to a east blue sea king, and Mihawk lost interest in fighting Shanks after Shanks lost his arm.
Yeah Oda hasn't treated Big Mom the best but don't act like the other Yonko's are being treated any better, also other than Oda's bias towards Nami he has never been good when it comes to writing female characters.
Touche.
But none of the other top tiers have ever been treated like such clowns. None of the others have had their enraged attacks blocked by Chopper, blitzed by Brook, knocked off by Jinbe, and then proceed to nearly die of hunger - only to be pitied by her enemies.
None of them has ever had amnesia, and they have never got caught lacking by a commander level foe; while getting their skull caved in by another.
While it's true that Oda cannot write female characters bar probably Nami, and to an extent Boa to save his life, it's not enough of an excuse for her poor showings. She's suppose to be a top tier and she's absolutely lacking comparatively speaking.
This arc might clown Kaido though so I might change my opinion later, but for now she's really really poor and she will not be killing anyone, let alone Garp.