Yeah, I'm of the opinion that Doffy won't die but that Law will at least show interest in killing a prone Doffy in the next few chapters.
Fuji will probably step in to claim Doflamingo and use him in his case for the abolishment of the shichibukai system.
I personally don't mind what Oda does tbh there are so many options at this point:
Captured by Marines/Burgess/Revolutionaries.
Death and Fruit is captured by Burgess by his bag of tricks, Luffy then takes it from him while he fights Sabo - Would be a great fruit for Sanji. Lol
Can't really see Burgess coming out of this arc in good shape with how outnumbered he is.
Escape is still possible for Doffy
I guess it depends on just how hard Luffys King Kong hit him, if it hit him like it did the island it could have finished him off.
He would be buried under the rubble.
–- Update From New Post Merge ---
Yeah I have a feeling that Zoro is not that far behind Luffy even though Luffy has gotten much stronger over the TS. Maybe comparable to pre TS difference in their strength maybe a little less than that. This just makes me feel disappointed for Sanji cuz it looks like he didn't do all that much hopefully he takes down the Big Mom ship.
He will have his chance, personally I would have liked to see him have a fair fight with Vergo but Oda clearly wanted Luffy to have his big fight before Sanji or Zoro.