For me as much as I didn't like the cake chase it didn't ruin Big Mom's character for me, the only time I wasn't a huge fan of Big Mom's character was during the cake chase and when she was O-Lin during Act 2 of Wano(which imo was even worse). The only time Big Mom would have been ruined as a character for me is if she became an ally during the WCI arc, some people want to put a lot of the blame on Big Mom but I think some of the blame should go to Oda who imo is not very great when it comes to writing female characters.
A character is what the creator makes them to be. If they are executed into the storyline as intended then the creator has succeeded.
If they are not executed into the storyline as intended then the creator has failed.
Oda failed hard with Linlin.
Even though I like Big Mom and will sometimes defend her, I don't think her character is perfect or even the best.
Never have I witnessed a major series antagonist get outshined by their own subordinate in their own arc. That is straight up disgraceful for a major series antagonist, especially one that has been hyped by the author for hundreds of chapters in advance.
No I don't think Big Mom is a bad character just because some people like you may think that doesn't mean everyone will think the same, she has her flaws but she also has stuff that makes some people like her character.
Anyone can “like” anything for any superficial reasoning. One can “like” a character based on nothing but their design such as myself with Urouge. My own fondness for Urouge’s character design does not make him an objectively good character though.
If I thought long and hard about every single character in One Piece and ranked them all purely on objective quality then I highly doubt Urouge would even make it into the Top 150.
I know plenty of people making fun of Kaido and some Big Mom fans including myself were in a I told you this would happen to some of the Kaido fans. This was because some of the Kaido fans thought that Kaido would be treated as a perfect character, and that no one would make fun of him but that didn't end up being the case.
His portrayal will likely shoot through the roof during the Wano arc climax. That still will not fix his lack of personality though. Oda will have to address that issue specifically if he ever intends to fix it.