Tbh, I'd be pretty pissed if Big Mom was dropped this arc. The whole point of this arc, IMO, was to show just how huge the gap is between the Strawhats and the Yonko and to really hammer home that they are NOT ready for that shit yet.
I think Luffy vs Dogtooth is enough of a showdown to end this arc on, then Sanji calms Big Mom down with the cake and they just about manage to slip away.
Then after they get wrecked in Wano, they have another time skip, but WAY longer this time... I mean at LEAST 5 years, and post timeskip Luffy is ready to tangle with Yonko.