I just played a game where I had the quest for “Play 3 Naga or Dragons” with the reward being “Hidden Body: Discover a minion of your Tavern Tier. (Can be earned endlessly!)” and it was practically unplayable in the late game.
As I was playing a Naga build, trying to play all of the Naga I got while being able to play all of the spellcraft spells before the turn timer was finished was impossible with the 7 second Quest completion animation (on top of having to select a minion as well).
If this combo is possible, there should be a way to either shorten or skip the Quest completion animation as there was never enough time to fully optimize my gameplay with just the animation taking up half of my turn.