It is that simple, you're definitely overcomplicating this, beyond what is actually happening.

The gamepad is the cockpit, that cockpit cannot let the player see an external view of the craft, from a birdseye view locking down at the craft, because the cockpit is inside of the Arwing. The gamepad is the view through fox's eyes (unless the role of image output is reversed with the camera being on the Gamepad and Cockpit being on the TV), so when he's inside of the craft he's never going to be able to see anything besides what he can view through the glass of the cockpit, the camera has limitations, everything you see is connected, across both the TV output and Gamepad images.

The gamepad follows the same limitations of viewing angle that any pilot would have in real life, the main screen and gamepad don't have completely different perspectives, in the sense of one being truly unbound from the other, when the two are on opposing sides of view they're still always a part of the same image.

The Gamepad has never been shown using a top down view of the the craft or surrounding environment, so I really don't get where you're getting this idea from, because that's never been shown in any of the Nintendo Directs. The angles can definitely be extreme and rendered within the same image pass, as a developer you're representing an image in 3D space.

Think of this like a multimonitor set-up.

It is that simple, you're definitely overcomplicating this, beyond what is actually happening.

The gamepad is the cockpit, that cockpit cannot let the player see an external view of the craft, from a birdseye view locking down at the craft, because the cockpit is inside of the Arwing. The gamepad is the view through fox's eyes (unless the role of image output is reversed with the camera being on the Gamepad and Cockpit being on the TV), so when he's inside of the craft he's never going to be able to see anything besides what he can view through the glass of the cockpit, the camera has limitations, everything you see is connected, across both the TV output and Gamepad images.

The gamepad follows the same limitations of viewing angle that any pilot would have in real life, the main screen and gamepad don't have completely different perspectives, in the sense of one being truly unbound from the other, when the two are on opposing sides of view they're still always a part of the same image.

The Gamepad has never been shown using a top down view of the the craft or surrounding environment, so I really don't get where you're getting this idea from, because that's never been shown in any of the Nintendo Directs. The angles can definitely be extreme and rendered within the same image pass, as a developer you're representing an image in 3D space.

Think of this like a multimonitor set-up.

There were multiple instances in the Treehouse footage where the Gamepad screen is aimed at an almost 90 degree angle to the main screen. The Gamepad does not show the interior of the cockpit, you can look down as if the whole cockpit was transparent. See 9:38 here for instance: https://www.youtube.com/watch?v=33Sr-oa83VY

It's like this; from where you are sitting at your computer, look up at the ceiling. Notice how you're not just seeing a zoomed in view of what you could see facing forwards. You are seeing things you couldn't see while looking straight ahead.

The Gamepad is by necessity a separately rendered perspective. This is why the graphics are compromised.

What about when the i-Direct is in a complete different room solving puzzles, and opening doors.

I've already dealt with this, wider field of view than 90 degrees creates one larger image that the Wii U displays a portion of on the main screen and the rest on the gamepad, zoomed in, with pillars laid in front to represent the cockpit.

Looking at the 9:38 section of gameplay on your youtube link doesn't show fox looking through the floor of the Arwing, it's just a portion of the same image, looking over the mountain.

Of course you're not seeing a zoomed in image  in real life, this isn't a video game, with a person having access to two viewpoints, one from outside of you, behind your head and another through your eyes. The gamepad image in the link just proves my point. The gamepad image is by necessity actually using a portion of one wide image, not some unique render.

The graphics are what they can be on Wii U's hardware, I mean it's got about 2X the performance of PS3 or 360, it's more efficient, in raw Flops it's a bit less than 2X the power of those machines, they had 720p 30FPS in similar levels of visuals, without some modern features like Screen Space reflections and Wii U's running that at 60FPS, it's not doing 2 images, with one being 720p and the other 480p at 60FPS, that's beyond it's hardware.

That's a separate instance, yeah in that portion of the game there's a separate render at 480p on the gamepad, but the difference there is that the main ship being displayed on the TV image isn't flying around, dogfighting a bunch of enemies and it's staying still.

From a rendering perspective the main screen would be very predictable, the hardware doesn't have to do much on the main screen there, so a unique render on the gamepad is easy.