The RPG idea is something that has been tried for ages - the earliest example I can remember is the "Chocobo World" minigame on specific interactive memory cartridges for Final Fantasy VIII for the Playstation I. More recent examples include the Game Boy integration with the Wii and the default controller screen for the Wii U console.

None of these attempts ended up being very successful with the exception of the wildly successful Nintendo DS, which is different in a lot of ways (in that the real estate size between the touch screen and the real screen is equal).

The objection that a lot of people here have to the touch bar is that it's a sort-of-nice-to-have, never-essential feature used on very few machines, and these are the sorts of features that developers instinctively smell danger around.