No, I mean specifically when would that theme fit into which moments of gameplay? The soundtrack of BOTW changes dynamically depending on the actions and locations of the character the stimuli that surround them. As for suggesting the OoT overworld theme, that is a suggestion that falls under the "opinions can be wrong" category. At no location nor situation would the loud & bombastic OoT overworld theme fit thematically with anything that is happening in BOTW.
The OOT theme is not loud or bombastic!
You're narrowly focused on the idea of fitting music to particular gameplay or map sections. Which is fine, games have been doing that for a long time now. It's not some sort of unique achievement of BOTW, much less an argument for its quality. I'm talking about the impact the music makes when they go to it.
For instance, the battle music is not good in BOTW, but at least it conveys some excitement. In that sense it fits a battle, but it also achieves something emotionally too.
When the piano motifs cut into BOTW, they are not necessarily being fitted into something. And they are not accomplishing anything. The natural world has already been described graphically and with sound design. The poster above likened it to a hike. Did the graphics and the soundscape create that feeling? If so, the music does nothing to add to the experience. Are the graphics and sound design an empty slate, and we just project the feeling of a natural, pristine world because the music told us to? Then I stand by my statement, no approach could be more boring than the one Nintendo opted for.
The Zelda 1 overworld theme does not in any way fit into the ugly, brown, simplistic grid based world of the first game. It completely rescues it and breathes the feeling of adventure into it. OOT's theme is not about fitting into Hyrule Field. Its goal is to sell Hyrule Field and the adventure that it kicks off.
You're acting like they had no margin to select the mood of this game based on the particular variety of climbing, or sailing, or landscapes you find yourself in. As if they could not have ascribed a feeling of adventure to climbing, or of danger to sailing, or of mystery to one of the landscapes.
Since you won't fill me in on the mood of the game, which will remain a mystery I guess, maybe you can tell me why, in defense of the soundtrack, people tend to post music that is the antithesis of everything in the overworld that you're celebrating? Why is no one able to defend the endless piano motifs of the overworld without referring to Hateno Village, or without damning it with the faintest of praise that it 'fits,' or through robotically describing how it changes depending on what you're doing?
Why does this music need so much explaining when past Zelda music, and indeed, other tracks in BOTW, pretty much speak for themselves?