The thing I keep coming back to is that this is a story about two people, and Rockstar has never done that

Every one of these games has been about a man and his associates. Even V, with three protagonists, was three separate men who happened to be in the same city.

This is two people in one relationship. The switching mechanic is not about variety this time, it is about perspective on the same situation. When you swap to Jason you are not swapping to a different life, you are swapping to the other side of the same one.

That is a genuinely new thing for them and I do not think the marketing has communicated how different it is.