Nintendo hasn't really been known to throw in customizable difficulty options for their Legend of Zelda games, but the upcoming Breath of the Wild will actually feature a brand new Pro mode and they revealed what it does.
VG 24/7 picked up the news from a bit of investigative journalism done by YouTuber Gehab. Over on Reddit he asked the community what they would like him to investigate while he attended the Nintendo Switch event live and in person. Gehab managed to uncover that if you go into the options settings in Legend of Zelda: Breath of the Wild, you can modify things like aiming with the motion controls, modifying the camera sensitivity and modifying the HUD mode where you can set to "Pro Mode".
So what does Pro Mode do exactly? According to Gehab, the Pro Mode removes the mini-map, the temperature meter and the sound indicator at the bottom right-hand corner of the screen. The only thing that still displays is the life bar, so you can see how much life you have left. It's not a huge thing, but for more hardcore players looking for an extra bit of challenge, I can imagine it being useful for those kinds of gamers.
Unfortunately he didn't get to mess around with the settings too much or find out if Breath of the Wild will have additional options beyond the Pro Mode. We'll have to wait until March 3rd to find out if they have extra settings regarding the HUD in the options menu.
How much will this actually affect the gameplay? We don't really know. Sneaking around and making noises is more visually contextual than audibly contextual. In games like Metal Gear Solid or Splinter Cell, it was absolutely essential to monitor your audio levels and keep track of the visual on-screen indicator because you couldn't always see if someone was around the corner who might hear you. We don't really know how important the audiometer is in the grand scheme of things in Legend of Zelda: Breath of the Wild.
As for the temperature and mini-map not being visible... I imagine that could make very difficult for some players. Link, of course, would likely have animations showing he's chilly, so you would know when to get a fire going and get the little elf-ling nice and toasty. Not having the mini-map on screen could be a real pain, especially during dungeon runs. But again, this all depends on how the maps are setup and how easy it will be to backtrack and navigate the open world based visual cues and landmarks.
Gehab also brings out some other interesting points about the functionality of the Nintendo Switch, mostly in regards to the fact that the Pro Controller feels more comfortable than the Joy-Con, and that when playing with the Joy-Cons in the undocked mode the buttons can feel kind of too close together when you're using one controller in both hands. The Joy-Cons are definitely tiny. However, you likely won't be playing a game like The Legend of Zelda: Breath of the Wild with a single Joy-Con controller.