MaRo started a "New World Order" (http://magic.wizards.com/en/articles/archive/making-magic/ne...) design approach in 2011, where they try to manage some of the complexity by making commons and uncommons have less and/or easier abilities. It sound reasonable, as casual players have a lot more commons and uncommons than rares and mythical rares, and it makes learning/enjoyment curve much less steep. Some experienced players associate NWO with "dumbing down the game".