My idea is to make it so you can tame cows because right now they are pretty useless.So how you would tame it would be first you will have to craft a wood brace.You will have to craft it just like a boat but upside down when you are done you can place it on the cow and it will follow you like a tamed wolf "but slower" and you can make it stay where you want it.
Then to craft the cart you will need 3 wood planks 3 wool and two sticks to make this you will make the wood to look flat on the bottom than on the top place the wool on the top three spaces than the two sticks on the middle slot on the left and right side.Than you will need to craft the wheels you will need 4 wood planks and one stick for each wheel you craft it by putting one wood plank on the top middle slot two on the middle side slots and one on the bottom middle slot than just put the stick in the very middle.
What the cart does is when you click on it it is like a chest inside so you can store building supplies without having to run back and forth from your chest in your house to your building area.The storing area is the same size as two large chests.This will help the game by having it be not so annoying from running back and forth.