A couple of enchantments couldn't be obtained from enchanting tables previously, but if you had an enchanted book with such an enchantment, you could still apply it at an anvil.

• All armor pieces can now get Thorns at enchanting tables, previously only chest plates were able to get it
• Axes can now get Sharpness / Smite / Bane of Arthropods at enchanting tables

Specifically for axes this really clutters the available enchantment pool and makes it harder to get tool enchantments such as Efficiency / Unbreaking / Silk Touch / Fortune which most people probably want.

This issue comes from EnchantmentHelper::getAvailableEnchantmentResults (the method responsible for picking enchanting table results) now calling Enchantment::canEnchant (for deciding if an enchantment is compatible with an item), when it was previously calling the now replaced EnchantmentCategory::canEnchant which didn't include the additional items from per enchantment Enchantment::canEnchant overrides.

Also on another note, while it's really great to have this new flexibility for controlling enchantment application via tags, why stick with the old enchantment category concept?
Like if I want e.g. tridents to accept Looting I can do that now, by adding minecraft:trident to #enchantable/sword, which is great, but it will also allow tridents to accept e.g. Fire Aspect at the same time which might not be something I want.
Why not just allow for one tag per enchantment?