This tavern brawl that always gives a mana-curve topdeck (when possible) should not allow questlines, as questline priest can guarantee a win on turn 10. All they have to do is have no 10-drop, and have a good curve tailored towards surviving until turn 10.
There’s a ton of decks that can beat them by turn 10.
Deathrattle rogue seals the game around turn 5/6 so no worries