As far as priest is concerned, I have two thoughts.
What I hope they get is some thief priest support finally. Something like: Play a card that started in your opponent's deck -> add a copy of Mind Vision to your hand Play two cards that started in your opponent's deck ->add a copy of Thoughtsteal to your hand Play four cards that started in your opponent's deck ->For the rest of the game: At the start of your turn Discover a card in your opponent's deck. Draw it.
Sure lots of people might hate it, but they are the kind of people that hate priest regardless. My other thought might be better and more powerful, if less interesting and that is for the questline be to both deal damage and restore health. Perhaps with a limitation like "in one turn" or "with spells and your hero power." Either way, Devouring Plague and Holy Nova would both go a long way. As for the reward, would a permanent Prophet Velen effect really be that outlandish given what we have seen so far? Also remember that standard priest has zero face damage beyond shadowform, so it wouldn't be as explosive as mage's current reward.
As far as priest is concerned, I have two thoughts.
What I hope they get is some thief priest support finally. Something like:
Play a card that started in your opponent's deck -> add a copy of Mind Vision to your hand
Play two cards that started in your opponent's deck ->add a copy of Thoughtsteal to your hand
Play four cards that started in your opponent's deck ->For the rest of the game: At the start of your turn Discover a card in your opponent's deck. Draw it.
Sure lots of people might hate it, but they are the kind of people that hate priest regardless. My other thought might be better and more powerful, if less interesting and that is for the questline be to both deal damage and restore health. Perhaps with a limitation like "in one turn" or "with spells and your hero power." Either way, Devouring Plague and Holy Nova would both go a long way. As for the reward, would a permanent Prophet Velen effect really be that outlandish given what we have seen so far? Also remember that standard priest has zero face damage beyond shadowform, so it wouldn't be as explosive as mage's current reward.