Region wise villager trades and quests

One of the best features I loved about village trade rebalance is the region wise trade dependence. Especially for high ranking trades. I was thinking that we make the region locked trades a vanilla feature and keep the highest trade levels locked for a villager quest. So fortune 3 for example should be locked, even for a master librarian, but it'll give a complicated quest (like finding a rare enchantment/curse or a rare item that it wants to study), which after finishing would unlock the fortune 3 trade. Same for mending and other enchantments. Mending would have the most difficult quest, which is already cool as you gotta build a village to begin this. To ease the jungle and swamp village construction, I think it would be cool to have structures where you are guaranteed to find zombie villagers who you can cure to get the villager variant you need. This would also solve the villager transportation problem.