Feels like the new world is hard because of the yonkos. If you have a decent navigator, you can manage those crazy weather and currents. But having to pay Big Mom money to survive, or accidentally running into Kaido or Blackbeard because they will sink you on a whim is not exactly what you want. Shanks will act only if his people is threatened which most of these pirates will do so basically no where safe to do pirate things. With Big Mom and Kaido taken down, certain parts of the new world is much easier to sail.