Like I said, it is my personal opinion, but: Villager trading mechanics and iron farms are too strong. They make a large part of the game unnecessary to play and thus should be nerfed.
Without villagers I will have to combine different gameplay mechanics to get my resources (mining for diamonds, iron, redstone, lapis; animals, crops, exploration to get some resources like ender pearls, I need to find XP to get enchantments, etcetera). With villagers you can replace the start- and mid-game with setting up your trading hall, which is not fun at all (everyone hates villager pathfinding and all the little ways they can lose their assigned workstation) and after that you can go directly to beating the dragon and finishing the game.
I have only been playing a couple of years, trading was already there when I started. How was the reception of the villagers trading mechanics? Why did people think this was a good idea?
I wish that villagers were never implemented on first place. If all development time poured into villagers was spent in other gameplay systems, the game would be considerably better.
But it seems to me that Mojang has a tendency to implement RPG features in Minecraft, without good reasons to do so. XP and levels were like this, too. And RPGs have NPCs trading with you, so Minecraft “gotta have NPCs”, no further reason.
Because they were outright useless before trading.