I just wanted to make a couple predictions and see what other people think will be in the future for this game.
I believe the "songs" cards are going to be very sought after. I would say valuable, but im not sure how individual card values work in this style of game. i love these cards, hey are extremely useful, especially since they run on any resourse type and are cheap. Being able to change resourse generation so easy, is fantastic and powerful. These cards give options.....whole deckbuilding options.
I imagine at some point we will see heroes in the future that actually have 2 resource icons to start.