> This is also why Snecko Eye (the relic that gives +2 draw every turn and randomizes card cost) is arguably the best boss relic. Even if you only get to play one 3 cost card, it's more likely to be the best card in your deck.

I can't agree with this. Snecko Eye is very strong, but playing a 3-cost card will cripple you. It's strong because you draw a lot of cheap cards -- the lesson of Snecko Eye is that playing several cards is better than playing one card, even if the cards you got to play were chosen randomly.