After reading the latest chapter my head is full of ideas and speculations. Since I can't find any prediction scripts to keep me interested, I figured a discussion blog wouldn't be too bad.
1. The only-legs guy. I'm sure he's a samurai of Wa no Kuni. He said he could sense their auras, which sounds like Kenbunshoku Haki to me. And as for how he ended up as only a lower-half, there are a few possibilities.
a. Trafalgar Law is the most likely culprit. We've seen before that he can seperate people's bodies. b. Buggy. I think Buggy could have improved his Akuma no Mi ability and found a way to seperate other people's bodies too. It's a suuuuuper long-shot, but I'm just throwing around ideas here. c. Doflamingo. We saw by the way he mysteriously cut off Oars Jr.'s leg that he can somehow cut up people's bodies. Of course, the problem is that when he does it, there's blood.
2. Shichibukai. Who could he be talking about? All three of the above-mentioned guys are candidates, in my mind. Maybe Law became a shichibukai in the two years that passed, although I highly doubt it. It could also be a totally new guy. At the end of the war the Shichibukai were reduced to just four; Mihawk, Hancock, Doflamingo and Kuma. I'm sure Buggy was given one spot, although if he was it's only because of the powerful crew he commands and not his own strength, obviously.
3. The mysterious kidnappers. They had the initials P.H. on their suits and referred to an M (Master). Are there any guys or crews with the initials P.H.? Who could Master M be? Moria? Magellan? (After all, they used a type of gas and wore biohazard suits with gas masks, which should be standard equipment for people who spend a lot of time around Magellan) P.H. could refer to Punk Hazard, in which case these guys may be people who were stationed at the World Government/Marine institution that was on the island.
4. The condition of the island. Half scorched, half frozen (according to Nami and the distress call). What could have done it? Akuma no Mi abilities? It happened four years ago, so before the start of the story. It could be a fight occurred there between Ace and Aokiji (long-shot). Maybe there are other dragons there, and maybe the dragons of the One Piece universe come in different varieties, like fire-breathing, ice-breathing, etc. like in Fairy Tail.
Smoker's coming soon. We also know that there is a Shichibukai in play, as well as a samurai from the Wa no Kuni. And dragons. And whoever is from the base/institution that used to be in Punk Hazard. And then there's Big Mom too. I have high hopes for this arc. I think it's going to crap many a pants.