This is the Priest Class Tree, that I made, from a section of the Hero Guide over at the community discord. Decided to post the image here, for those who don’t have discord and just want to know the Priest information.
This is my opinion:
At this moment, in order of strength for Arena .
Evocation: Proper placement to use consistently and resets cooldowns, do I need to say more.
Guardian Soul: No opinion, haven’t tested.
Purge: Situational, for Paladins, heavy Soul Priests/Arch Wizards, and heavy Priests teams.
Cleanse: Situational when facing teams that focus on status conditions.