Card Draw is extremely powerful. Getting to play the best cards for the situation you're in every turn makes you take far less damage in fights. Battle Trance is worth taking very highly for at least the first half of most runs. Keep an eye out for the interactions with cards like Fiend Fire or an upgraded Armaments in particular. In my experience, my best decks do eventually stop wanting Battle Trance. In Act 2 the downside becomes a large enough consideration to consider skipping it.
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