To improve and enrich agriculture and animal farming.

Hello. I'd like to begin by mentioning that I've seen ideas for improving
 agricultural and livestock systems, such as permaculture. My perspective 
is more holistic.

Adding a system that depletes the soil through monoculture farming is an 
idea worth exploring, in my opinion. But that's not all. Pigs never existed 
in the wild in prehistoric times. They are a human creation resulting from 
the natural selection of early farmers.

I therefore propose implementing a natural selection system for our livestock.
We could introduce warthogs or wild boars, depending on the biome's 
temperature, to tame and breed them into pigs. We could also introduce yaks 
or bison to produce cows. And, after taming mountain goats, we could obtain 
sheep (I don't know the ancestor of the sheep xD). To keep things simple,
we could aim to produce chickens, sheep, cows, and pigs in a minimum of three 
generations. Or more or less, as you prefer.

This might be a big undertaking for you, Mojang... especially since you've 
already worked on variations of the animals I mentioned (and babies too!). 
But I think it'll be worth the effort. With the ancestors of our farm animals,
you'll enrich the biodiversity of Minecraft's biomes.

And in terms of agriculture, implement lettuce to tame rabbits (rabbits never 
eat carrots in the wild). Implement tomatoes, for example, to prepare for a 
possible future food update.

There you have it. I hope I've been clear enough and that the moderators will 
accept this suggestion :)