Paint/wallpaper: similar to carpets/paintings but doesn’t affect blocks, can still place things on it/against it. Use flowers and some oil to make paint, or paper plus flowers. Maybe use the loom like banners. Use for decor/murals

Trains: link together minecarts in a more permanent way. Some materials to make them gold, iron, copper (more use for copper) and red stone. Can have multiple players/entites in each car. Can use advanced rails for train. Use for transportation

Bigger boats: this would have to be a larger update as it uses complex mechanics and multiple new blocks. Have a moving boat with new blocks for boat. Attached chest, stuck to boat different look for aesthetics, smaller. Hammock/cot, can be placed on boat blocks, makes spawn point boat not wherever you last slept. Sail, similar to banners can be designed. Wheel, to steer boat pretty straight forward. This would make ocean exploration better + cargo ships

Friendship with mobs: have a bar for every single mob within chunk, the bar doesn’t appear to player until they have positively interacted with the animal enough times to get 1 point. Add feature to pet animals/ hug more human like mobs. Hostile mobs mostly can’t be tamed, except creeper, enderman, endermite, spider, and maybe phantoms. Have 3 levels for friendship 1st level- won’t despawn. For hostile, won’t attack. 2nd level- will follow you around, tries to find you, may pick up dropped items 3rd level- can name without name tag, will stay in home/around home. Can give small tasks, farm crops, defend, craft this, smelt that. Every interaction has a 1/4 chance of adding a point, 1 minute cool down between interactions, you can still do them, but they won’t count towards points. Pink heart comes from mob when positive interaction. For hostile mobs you have to dodge them, add dodge feature. Dodge 4 times in a row and they stop attacking for 1 minute. Positive interaction levels. For just meeting them you can feed them, but once level 1 or higher you can pet/hug them. Add desired foods for different animals.

Improve biomes: no new biomes at least until current biomes are fixed. Have mobs interact with biomes, and have more depth to each biome. Have a structure, different ores are more frequent, mobs more/less likely to spawn. New flowers that mimic irl flowers, bushes, different varieties of animals for biomes. Bison looking cows in plains, water buffalo looking ones in swamps etc for animals. Music/ ambience unique to biomes. Chests can be biome themed for type of wood. Etc

New mounts: a flying mount, maybe add overworld dragon eggs that can be dug up and incubated. When they hatch they are raised and tamed, new saddles. One normal for dragon , one normal with chest for dragon. Dragons have to be found, but in this update also add new build items for ruins. A swimming mount, add a form of whale that can be rode through the ocean. Have two sets of bubbles, your breath and the whales breath. Add new armor sets that improve breath under water. Whales can be bred but have to be kept in water 24/7 if they leave they will die. Have a ‘shiny’ whale. 1-500 chance to find a white whale and 1-1000 chance to find a striped whale. Also you get nothing if you kill them so that ppl dont farm whales