Terrarium worlds

Hi! This is a pretty simple idea I got after playing a bit on indev versions. Simply put, imagine that when you create a world you can set "terrarium" in world type, and you can choose a biome (one that has trees). It would be a finite world that isn't huge, would be like 16 chunks big maximum (this even seems too big to me). There would be no structures, no nether or end. The block palette would also be kinda limited (not sure at what point but it would be related to the biome, like cherry trees biome means no other type of wood). I think it would be a great way to bring back some of what was the core of minecraft, like the feeling of isolation, the simplicity without being overwhelmed by the possibilities. Also I discovered the isometric screenshots and it would make something awesome if it could be there too (I suggest look it up if you don't know what it is). Having a non-infinite world would also make every action meaningful. Killing all animals would mean you won't have meat, wool or feathers ever again. Losing anything would also be terrible. And when you mined everything, the only way to get stone again would be with water and lava. Imagine a fully finished world that you built carefully, with your buildings on it, and then at the end you take an isometric screenshot, that becomes your phone background, that's pretty lovely. Anyway, I feel this would really add something. I could be wrong though, so feedback is appreciated! Thanks!