I’m not upset about the extra effort for Mending. I’m upset that the only way to get Efficiency from the villagers is not just the desert biome, but it’s also capped at III. In fact, all of the special guaranteed books once you level to Master (except for Silk Touch and Mending) are lower-level. It’s Efficiency III, Unbreaking II, Protection III, Sharpness III, and Fortune II. (Source) Not sure if I would be able to get maxed gear by combining villager enchants on an anvil anymore thanks to the prior work penalty and having to combine more things. I could always just luck out on an enchanting table and get Efficiency V, but I miss the reliable source of an enchant I liked instead of having to rely on RNG.
I’d be fine with the new requirements if the max rewards weren’t lower-level enchants. With the enchants being lower-level I feel no incentive to level anyone but the Silk Touch and Mending librarians to Master.
EDIT: I checked with the help of this tool and I can successfully get maxed tools with only the books I can get from the new villagers. Also tried to make a max sword in-game under the limits and it worked out. Not sure about armor but I frankly don’t personally care much about it. Still wish the books unlocked at Master weren’t capped so low, but my immediate worry about obtaining max tools and a max sword is assuaged.