While new and exciting interfaces and the design discussion for them is a good thought experiment, it is completely irrelevant to designers creating content for today’s technology.
The best we’re going to get is something along the lines of the STEM controller, HOTAS, or even just the run of the mill gamepad.
I havent seen the latest design of the STEM, however, it should be like an xbox controller cut in half. If you’re holding the right controller, there should be a trigger button, shoulder button. To the left, an analogue stick, to the right of that (and a bit up), 4 face buttons.
Basically, sort of a tricorder / phaser (from star trek) style of design, more or less.
As far as software side of things, the camera not only needs to follow a “true first person” pawn, it also needs to affect the bones of the character as well, just like the hand controllers we see on YT do.
Transitions… well yea. Fade to black, or something similar. Why not a 360 degree panorama image with game-tips around it? Disable player movement, but not camera, and you’re good to go.
Want to play a cinematic? Make the plyer a “ghost” or add a blur type effect around the vision borders and make the cinematic black and white, or washed out (make it seem like it’s a dream). You need to make it an actual level (no pre-rendering) so that convergence / 3d works right…