One other thing Product Architecture had figured out is that if we moved away from five decks, we would need a new way to make our decks. In the past, we had done it by color. Five is kind of the golden standard in Magic: everything works well in fives because of monocolors, two-color pairs, three-color combinations, and even four-color combinations. But this change came at a fortuitous time because we had definitely started to exhaust most of the color pairings.
So, the other excellent conclusion they had reached is that, instead of being built around color, the decks would be built around themes.
That's right: starting with Commander 2017 and moving forward, the Commander sets will be built around themes rather than color.