Wandering Traders Need Better Variety

We can all agree that Wandering Traders don't have the most useful trades for players most of the time, being most useful in Superflat worlds to get saplings, and with the recent Snapshot it seems like it won't get much better. Why buy a bucket of Water or Milk, when they're incredibly common items? There are much better ways to get Emeralds from other Villagers, like Fletchers or Leatherworkers, and players aren't that likely to give up their Iron Bucket if they should randomly run into a Trader on their travels.

With the recent removal of a few enchants from Librarian Trades, as well as the limits placed on a good sum of those still here, what if the Wandering Traders could offer some of those to the Player when they show up? They're collector's of oddities, moving around the world and picking up trades from other Villages. Who's to say the Wandering Trader didn't stop by a Desert to get a rare Efficiency V book? Maybe swinging by the far reaches of the Jungle to get Unbreaking III? Or perhaps they went sailing and found some enchantments for your Tridents while picking up a bit of Coral?

While the amount of those books would probably be limited, it would add a bit of anticipation for finding a Trader instead of resentment and annoyance, and be a great positive change to the mob.