As a fan coming from the original PS2 games and currently happy with 3DS titles I should say you’re absolutely right about your ideas. My main wish is that they’ll implement some aspects of Monster Hunter Online into a possible Switch game. Such as larger areas and gorgeous looking visuals.
In March 21 Toukiden 2 will release and it will be an open world hunting game as you suggested and Japanese reviews are very positive about that game. So an open world for MonHun could be great after all. As for the Monsters; I wish some training mechanics for them. I mean sometimes when you kill a monster you’ll end up it’s eggs and bring them to Village and when it’s hatched you could train the monster to fight alongside you. You can only bring one to the fight instead of Palicos and if it dies in action it’ll die permenantly for more emotinal side (if MonHun ever needs one anyway).
Again another aspect that could benefit from Switch is more story elements and more quest types (please no more “find 5 musroom quests”), also a real time physics engine could do marvels in enviromental interactions (such as breaking ice onto the monster to stun him, or cutting trees for blocking it’s movement). We’ll see the answers in the future but before any of this we’ll get a MonHun Generations XX HD for the west I guess. Which is also a good thing.
In the end it’ll be great on Switch.