Messing around with the new enchantments in SP creative for my own info before I waste my time in Blacraft.
Enchanted books:
1 enchantment per book but can be anything. Out of 64 books, got thorns and silk touch once. Unbreaking was reasonably common, so it might be worth it for amazing swords and armour (not cheaper than naming armour and swords though).
Protection vs other enchantments
Protection armour still protects from fire, although protection 4 does not replace fire protection 4 like it used to. So it just got nerfed a bit I'm guessing, still good though. Unlike what the wiki says, protection 4 boots aren't feather falling 4 boots. They did interestingly enough, act as a sort of respiration. Making the time underwater slightly longer and reduced drowning damage.
My opinion: fire resistance is much more valuable now. However, do not be sad if you get protection, it's useful just not as useful. Definitely more useful than blast protection and projectile protection.
Thorns enchantment
Right now you can (in creative) add thorns to all blocks. This is a bug, however from my tests you can only get thorns on a chestplate via enchanting. So I'm not sure if you can reasonably add thorns to all armour in survival. However, it was rare when I tried enchanting books for it. Besides, having it on all armour pieces won't multiply the effects so it's useless.
Basically, on chestplates there seems to be a 70% chance on getting thorns, if you don't get it you probably got ripped off.
Leggings only have one enchantment unless you add unbreaking to it (maybe thorns?), so hope for fire protection or protection. Boots and helmets appear to be mostly unchanged.