I'm on the "you'll always empty your hand" bandwagon. Especially since from what we've seen so far, card abilities in this game are very, very, very simplistic (hit this for X, remove some threat, draw a card, stun something, etc.). Those are not "situational" cards.

Yes, I can’t see an advantage to only playing a single card a turn rather than playing the best turn with the cards you have. The only disadvantage to cycling through your deck is having an extra encounter card. If you don’t maximise your card play, the Villain will play many many more additional cards over time compared to your out put, which seems objectively worse. If the Villain deck cycles, that adds an encounter every turn which is generally going to be a lot worse.