We're not bringing back the detailed models. They don't fit with the Minecraft style and are too laggy.
It's alright suggesting having an opinion to turn them on / off but then that means twice the work for us. The aim is the make all the assets in the same style as the game.
We've specifically designed 1.16 in this style, however we've also put a lot of work into 1.16 to allow people to change any model they want using resourcepacks. All blocks, entities and everything else you can think of will be able to be changed in a resourcepack