The mystic is an experiment that uses disciplines instead of spells. But the class's abilities could be replicated easily with spells. #DnD

— Jeremy Crawford (@JeremyECrawford) March 15, 2017

The mystic is an example of us testing a concept in UA: is it fun to represent a different mode of magic with a different subsystem? #DnD

— Jeremy Crawford (@JeremyECrawford) March 15, 2017

@BrandesStoddard The “clustering” effect of Disciplines is super interesting and does an awesome job of carrying theme. Indeed. Yet we could cluster spells in the same way. But we're experimenting with a non-spell approach.

— Jeremy Crawford (@JeremyECrawford) March 15, 2017

@JeremyECrawford Fun for a player who wants something different, or fun for a GM who has to learn a whole new system for that one player? 😉

— Chris Fontenot (@ChrisFontenot13) March 15, 2017

A class should be fun to play and for a DM to witness. If a new class is a headache for most DMs in playtesting, we change or cut it. #DnD https://t.co/uDDRxtQPPQ

— Jeremy Crawford (@JeremyECrawford) March 15, 2017