Something smallish I'd love to see in Vanilla Minecraft, is color coded Compasses. Being able to make a compass for each color of dye. And being able to make corresponding waypoint blocks to place in the world. Each color of compass would go with the same color waypoint block. And the compass would always point towards it's own waypoint. Don't make 'em too expensive to make, but they shouldn't be really easy either. Maybe something to do with redstone and gold? As well as compasses obviously.
My main reasoning, is that I hate the maps in Minecraft. They're mostly useless for me. And not all versions of Minecraft even have coordinates. Specifically Pocket Edition and Windows 10. So something that you could use, in Vanilla Minecraft, that'll help you set waypoints, and find your way over long distances for every version of the game, would help a lot.
As it is, if I play my Windows 10 version, I don't even want to stray too far from my house, because I don't wanna lose it. And I'm forced to use coordinates in other versions, which feels a bit cheaty to me.