I think current estimates,. 62-82 sq km, for Zelda's map size is appropriate for the game. It's sufficiently large enough to make the game really feel like a multi-regional world and not simply some playground Frankenstein of one, but not so immensely large that Nintendo will have struggled to include meaningful content at a reasonable density throughout it.
The only question now is; have they actually created compelling content and taken the time to learn the lessons of other open world games and the does and don'ts of such games from other series.
We all know the Zelda team is quite talented and creative, lets hope they were given the freedom to exercise those abilities within the game world.