Hearthstone, by virtue of being a virtual card game, could totally avoid the issue of power creep that's so prevalent in CCGs, by adjusting older cards to prevent them from falling behind. Yet, they still release cards that are almost identical to older cards, only slightly better by one point of something, obsoleting the older card, and introducing a boring new card that serves the exact same purpose as the older card you could have just buffed to fit that niche