Totally agree, This has been asked many times by many different people xD
The devs have already announced this, but it probably won’t arrive in the next update since that will focus on multiplayer.
This is because purple enchantments are not a superior alternative to blue ones, they are two different options with different unique enchantments.
But the system’s RNG is a problem for the gaming experience, Here I propose a detailed solution if you are interested: [The RNG Problem, The RNG Problem, Enchantment System Vs Gem System (Major Edits).