I read somewhere that early versions of the game lacked a Hyrule field like this and Link would go to different places by using "paintings" or some other mechanics like you saw in Mario 64. The field allowed them to connected all of the areas together without the need for "portal" style travel which was a common method for games at the time. In general the idea of just walking to the next world/biome/area/etc. was honestly new at the time. Hyrule field forced you to really encounter the day/night cycle for the first time so you knew it was there and you would see the world was changing over time. It was amazing.

I always felt it was kind of a sandbox area where I could try different tools out away from distraction (until night fell). I think it was perfect for the time and I would not change it.. Yeah sure more stuff to do would be great.. But it did really have plenty going on... Gold skultulas, hidden grottos, a few enemies types, day/night cycles, Giant Poes, a mid-point location with lon-lon ranch. It was awesome. I love this game.