Here's the issue with that. Oda can't just make Big Mom all of a sudden out of the blue a competent character without her going through a drastic personality shift. So if those gag like moments all of a sudden stop, it breaks the flow of how she has been written from day one. Building upon what has been established within the confines of her character is not bad writing. Breaking that pattern with no explanation would be.
She actually has been a completely different character (in terms of competence and threat factor) in the beginning.
Remember her at the start of WCI: She was portrayed as a cunning mastermind, who knew all steps from Luffy & Co. and even managed to fool Judge & Germa into a Red Wedding situation. Then she actually no-diffed Niji and Yonji on the rooftop, while her kids took care of Luffy and the rest.
She was actually really frightening back then.
Then her tantrum after the teaparty happened and suddenly Oda did a complete 180 on her. After that moment he solely used her for gag situations. In Wano she really has been one gigantic comedic relief and that's just bullshit.
The discrepancy of her original portrayal and how she is portrayed now is just idiotic. It's not about gag moments with her, the problem is that she is ONLY one gigantic gag since the teaparty.