Alright, so we mostly agree that old villagers (Post-1.14 ones) were directly OP but extremely RNG (I’ve seen YouTubers take several in-game days to get Mending) and the new snapshot villagers are annoying (they were annoying before, but you just hooked a breeder to a trading station, without caring about the biome), but not RNG, instead you depend on the biome configuration.
My idea: add artificial biomes. Like Terraria, have solutions sold by the wandering trader or brewed that make the block you used them another biome, and make them splash for an AOE effect, have baby villagers be one texture that doesn’t change by biome, and depending on what biome they grow in, they are one biome or another, and make them have discounts on the correct biome, but it doesn’t apply on an artificial biome.
Let me explain this: You have a Swamp villager selling Mending books for 21 emeralds each, and you place it in a Plains biome. No discount. If you place it in a swamp biome, you get an small discount, let’s say it now costs 19 emeralds. However, this does not apply in artificial biomes.
So what this is doing is saving you if there is not an specific biome near you, but also reward you for placing them in the correct biome. This idea can and will be polished with time, but this is a good explanation.
This is an interesting idea, but I don’t think it does a great job of addressing the issues with the villagers.
Imo, here are the big problems with the biome-specific librarian trades:
Artificial biomes don’t really solve either of these problems. It’s still extremely unintuitive. And even if you know how to do it, you’ll need to somehow obtain a jungle biome splash potion, throw it somewhere where you have a baby villager trapped, wait for it to grow up, and then trade it to master just to get an Unbreaking II trade.
I think that if swamp and jungle villages became a thing and if there were, idk, special enchanted book textures for each librarian type, the system would work really well. It’d encourage exploration and setting up paths (e.g., Nether highways) to villages in other biomes. As for Mending, I honestly think that the enchantment’s existence should really be revisited.