I don’t think Luffy should fight DoFlamingo, I prefer Law fight him (well I prefer Sanji vs DoFlamingo but that probably won’t happen. So yea Law).
Right now no one on Punk Hazard is on DoFlamingo’s league. Smoker being a Logia might be able to survive DoFlamingo cut, and Law might be able to counter DoFlamingos cuts with his own, but Luffy has no chance of beating DoFlamingo right now. DoFlamingo is a beast, he’s a Devil Fruit user (possibly) and he’s running over the sea from island to island with no back up, and a grin on his face. I honestly think he’s the strongest Shichibukai. He knows that no one on Punk hazard has a chance against him, he’s confident that he can kill everyone on that island by himself. I don’t think he’ll make it in time to meet the Strawhats, Law, and Smoker though. He’ll probably get there to late and see Monet and Vergo dead and he’ll just blow up the island himself and leave. I don’t think Oda will have DoFlamingo fight so early, because there’s no way someone won’t die.
If DoFlamingo gets there in time this is going to be like Kuma at Thriller Bark, except this time the Strawhats won’t be so lucky.
Would you like to see the Strawhat's have their bounty raised? At the least Sanj because he seems to be lacking in that area, and so is Zoro. I feel that their bounty should be a bit higher just because of what there capable and maybe I'll have to wait to see when they cause some more problems in the New World.
I would love for Sanji to get a bounty increase , and yes Zoro too. I think their biggest bounty increase will come after the Big Mom arc, since I’m pretty sure the government doesn’t care about Caesar Clown and Punk Hazard.
For now I think their (Luffy, Zoro, and Sanji) bounty should be somewhere around: