It is totally a long arc, but it isn't really longer than Dressrosa (or even Water 7) for now. According to random wikis that I found, these two were around 100 chapters too. But it's the normal thing for OP, the main arcs take FOREVER. And, considering that there are also other fights going on (all these Zoan-types will probably get a bit of action too, as will the other Straw Hats, I guess) it might become the longest arc. But than, the backstory is told, so it's not like with Enel, were we get near to the end, and than we get six chapters of backstory, or whatever that was.
I do hope we get an extended period of story snippets afterwards, though. These are always some of my favourite parts. I want to know more about the actual leader of the world government, I want to see Vivi, Shanks, Blackbeard, Sabo, and all the others again. I want to see how the world moved on, or something about how it will change again.
I just now realised, that the timeskip was more than ten years ago. Good lord! Thinking back on Water 7, for some reason, I thought the manga was going to end soon. Yeah, not quite.
Also, I really would like to visit Elba soon. That is the place where I had wanted to go for so long, and Big Mums backstory made me hungry for more. Oda can't skip that one, right? It feels like he promised, way back in Little Garden, that we would visit the land of the Giants at one point.
And finally, I want to finally learn something about that lost century, or whatever it was called. I'm hungry for more information, for the D., for the story on the Porneglyphs, and I finally want to meet someone from the Rebellion (forgot the name). Give me some information, Oda.
And finally, for real this time, I would like one or two shorter arcs. I enjoyed Wanokuni, and I loved visiting Big Mums island, but the short arc with the Minks was probably my favourite part of the whole post-timeskip era. It felt so un-formulaic and fresh. More of this, please. Let's do something short and fun, please.
Ok, I still got one more point. I still feel like, everything up to this point is the part of the New World, that is a reflection to the whole Crocodile arc (everything from entering the Grand Line, up to defeating Crocodile). At the start of the Grand Line, Luffy was a nobody, and there was a multi-story arc. Every island they visited offered an adventure, that had to do with Crocodiles mafia. Crocodile himself was on a new level, someone way stronger than Luffy had ever faced, and who was actually just above Luffys weight class. And he made a name, by defeating him. That was the point, when the Straw Hats became players on the Grand Line.
For the whole time the Straw Hats were in the New World (at the start in Fishmen Island, more precisely), we heard about Big Mum and Kaido. And, similar to how he fought against Crocodiles agents, he started fight with Big Mum. Don't remember the details, but Fishmen Island was her protectorat, and now it was his. Then, he picks up Mononosuke, similar to how Vivi joined his crew. Back then, this part of the story started, and now it will end. And Luffy, who was just a random pirate in the New World (powerful, but still one of many) will make a new name, as someone who defeated a Yonkou. That's when he becomes one of the final, top players.
I'm excited, is what I'm saying.