>>716091604All the Mario RPGs are extremely linear when it comes to exploration and storytelling, while all the 3D collectathons give you a good deal of freedom to tackle the challenges in whatever order you want. An open world RPG would ideally meld the two ideas, so that you are building up Mario's stats but not being confined to corridors and breadcrumb trails. It would be like Breath of the Wild in RPG form, where you can tackle the final boss whenever you think you're ready, and you can build up your strength at any point on the map as you wish.