If big mom dies...

[Blackangel]

if big mom falls now, it would create a panic and marines would rush to hear home. things would get even worse

 

[Kaname]

It would be game over to that yonko and big mom pirates. Luffy doesn't have to fight four yonko's to get to be a pirate kind. I would rather see her die like this

 

[Blackangel]

now as you see she is a lot stronger and i don't think anyone can ever stop her, if she goes total crazy like that in her hunger pangs. even luffy couldn't land a good punch on her.

 

[Kaname]

You are forgetting that luffy is the MC. He can defeat anyone and this story would never let him get killed. He would stop her but I don't know how.