The only difficult thing here is how to make it work in combat. Even monster hunter tried it and backed off from it on the next game, only keeping the leviathan type monsters and some fish ones that most people dislike. The Tideripper does have a leviathan type feel to it, the Leatherback turtle could work like a mix of tideripper and shellsnapper so you got that.
The Whale though... I think we could use something like the San Francisco underwater city and the fights in Deathstranding. We have buildings rising just a bit above water while the whale smashes against them, dropping us to the water and we have to climb up again. It should have tons of range weaponry, perhaps be able to surface and smash us and then retreat to the water again and, of course, jump above buildings like a rockbreaker. We could enhance the mobility of the character with the pullcaster and shieldwing, jumping from building to building.
So its possible, just a lot of work for just one machine perhaps... still I hope they do something similar. I really want a big whale to fight agains.
