For sure I can say the Brass catcher, husbandry, and quivers are great ideas!
I've always been a miner farmer so the husbandry update would be right up my alley.
Always been wanting more crops in the base game like tomatoes, rice, and onions.
But being able to raise animals would be great! I believe A21 update included a feature where zombies would eat dead animals so having to protect your farm would be interesting as farm animals I imagine would be targeted. Plus adding more animals to the game would always be nice.
My self and a few friends have been wanting a simple monorail track for mining for years. Nothing crazy, just something that would maybe hang off the ceilings and allow you to transport crates or even yourself along the rail.