Unlockable enchanting

I find enchanting to random. Instead what if each enchantment could be added at a set cost. Thorns 1 equal 5 level ect. To make this not OP and add a challenge to the player, they need to unlock these enchantments. For example the player needs to collect 100 cactus to get thorns 1 and let day 10,000 cactus for thorns 3. Fire aspect could be linked to blazes and mending linked to repair a 100 tools on an anvil. This simple change would remove the random element and give player a challenge to aim for; a bit like getting the achievements for the first time. Unlike the achievements, player will need to create large farms, redstone contraptions or explore to get their ideal enchantments and early level enchantments will feel more useful as they can be used while trying to unlock the next level up.