Regarding the possibility of future additional content, there's something interesting about the "compartment like" design of some portions of games like Breath of the Wild and Odyssey. In the case of the former it's related to the modular design of Shrines and in the later the Challenge Rooms.
I hope we get a Galaxy 2 style sequel or plenty of DLC, I have not beaten it fully yet, but I know I will want more ;).
Is a positive for developers in the sense that it's a clever design sortcut but it also benefits the prospects of DLC as it takes less resources to make content of good quality. These spaces been isoleted from level and not neccesarily require to be thematically and geographically alined with it means changing it's layout for new content is faster.
In the end is up to Nintendo if they want to offer more advanced Shrines or Challenge Rooms. Resource and time wise there's not much of an obstacle.