Great find.
The game looks amazing, really organic and interactive, which isn't really something that open world games tackle in terms of puzzle solving.
But yes, while we now have confirmation, there are a lot of signs that the GamePad has been decoupled from the game. At the Game Awards they made a big deal showing a maps-like app interface for the GamePad screen, which had dedicated zoom touch buttons, touchscreen waypoint placing and swipe-to-pan controls.
What we saw in yesterday's footage was a large move away from that kind of interface, instead any interaction with the Sheikah slate seems to be entirely button and D-Pad/Sticks driven, rather being unique to the second screen. I wonder whether it'll mirror the TV display when you bring up the scope so you can look through the second screen, but it definitely feels a lot less "special" now, given our mental connection between in-game smart controllers and the one in our hands.
Aonuma's excuse for gutting the GamePad map is also pretty weak, since I'm sure a minimap would have existed in tandem with the GamePad's interactive, async one.
If he's telling the truth though, I'm not sure it's a move I appreciate. Detail-rich Mini maps tend to lower your immersion in exploring the game world. Zelda has traditionally had great mini-maps which don't give away enough information such that you rely on them, so hopefully the same bodes true for BotW.