Come on.>Route 1 - forced down a single path to Iki Town>Iki Town - Nothing worthwhile to do but go to Mahalo Trail which is literally a hallway>Back to Iki Town, choose your starter>Route 1 - forced down a different linear path to Iki Town>Lillie comes to get you and you can't go to Iki Town or to the Pokémon Center west of your house, you can only go to Kukui's>Going west after that won't let you go past the Pokémon Center until the tutorial>Going west after that won't let you go past the Trainer school until all those tutorials>Hau'oli City has "freshly painted fences" that prevent you from going through it, making it a giant hallway with forced tutorials all the way up>You can't go onto Route 2 because Tauros again so you gotta go around the bend for more tutorials>Team Skull battle with Ilima at the end and now you can do Route 2>Forced berry farm>There's Guzma's house, a side hotel with nothing of value, and a diverging path that ended up being pointless because it leads to the exact same place as the other one
Good note: Hau'oli Cemetery. It's optional and exists as different area along the route and even has a special event if you choose to go back there after the trial.>Verdant Cavern as the trial site, simple stuff>Route 3 is linear with some branching paths that are less divergent than Route 2>Forced to go to Melemele Meadow for Lillie and Cosmog
Questionable note: Seaward Cave and Kala'e Bay. They're optional, but they're not exactly interesting locations.>Back to Iki Town by completing the circle to do the trial>Back to the ferry port to the next island which is pretty much the same thing
Decent note: Ten Carat Hill has a unique atmosphere but feels half-developed
And this is the whole game.