Well, I think that you focused specially in a general idea of the game. But like Treim, i can't say that having more than two colors is a bad idea. Let me explain. There is a nature card called enlightenment. It's a ultra-rare spell and in the old Battleforge, his cost was about an average of 1500 BFP. I can say that it is one of the bests spells in the whole game. When you cast it, you can play a card with ANY requirements (But I don't remember if you had to pay the card's cost). That card is awesome, because if you have a pure nature deck, you can play with shadow or fire cards if you want. Imagine that you have in your pure nature deck an Harvester. If you don't build 2 shadow orbs, you can't play the Harvester, but if you cast Enlightenment you can play with the Harvester without having to build the orbs. The T-Guide of every color are short, but I know that it will be changing with the time. However, excellent guide, it gives a general idea of the PvE decks and it incentivate player to play more PvE for the 12-players maps.