It has been confirmed that Legends won’t be open world.
Comments from the Pokemon Company has confirmed the game won’t be open world. Less like Zelda Breath of The Wild and more comparable to the likes of Monster Hunter.
Jubilife Village is the base of operations in Legends and you will travel to different parts of the Hisui region for your surveying quest.
“In Pokémon Legends: Arceus, Jubilife Village will serve as the base for surveying missions. After receiving an assignment or a request and preparing for their next excursion, players will set out from the village to study one of the various open areas of the Hisui region. After they finish the survey work, players will need to return once more to prepare for their next task. We look forward to sharing more information about exploring the Hisui region soon.”
Pokemon Legends Arceus releases on the Nintendo Switch January 28th 2022.
Source: Nintendo Everything