I think having really simple things would be cool. A sundial to tell time, using empty cans with string made from cloth to have conversations with people long across the map, and also instead of only using stones for arrows, using bones from animals for the tips. Once water is added to the game to be more prominent, fishing and making wells. Crafting personal vehicles like bikes, scooters, and skateboards. Also group transportation like tandem bikes, horse and carriage once horses get added, and rickshaws. Mountain climbing equipment would also be cool. Farming would be cool also planting fruit trees. Gardening in general would be fun. Brewing Alcohol would also be cool. Shovels and hoes would be cool. So would having a pet and livestock. So would an in game map that you can mark yourself. Also if we could make balls out of animal bladders and play catch that would be the most fun ever. Also tree houses and ladders would be cool.
I know that most of these ideas might be already on the drawing board, but these are just things that I think would be cool.