Who do you feel Big Mom shall deal with meanwhile? I'm thinking of Kidd and Killer in particular, doubt others will take on her soon, but I don't think they will probably defeat her at all. Also considering all the amount of portrayal Oda came up with since the times of FI, I would be pissed if it wasn't Luffy to ultimately, not necessarily this arc either, but it depends on how quickly Oda wants to end the manga I guess.