I've been wondering about it myself and it is to be considered that the quests use the respective League of EVIL/Explorers members as tthematic inspiration.

I feel like Priest could be something like "Heal yourself for X" to receive a passive hero power that forces the opponent to play with an open hand (since madame lazul is all about seeing the future and predictions and her minion version has to do with the opponent's hand as well)

For rogue I assume it could be something like "play x cards from another class" to gain a hero power like the advanture's "yoink" since rogue historically is the only class that doesn't feel broken with insane value generation due to its lack in AOE and healing

 Either a dynamic removal or sticky board presence. Honestly just seems like a good card.