I don't mind buying the new Duels core game every year, and sometimes I even buy the expansion sets. But after a few years I start to miss decks from older years. I can't really go back and play the older core games because the player base moves on to the newest year. Magic's player base has exploded, so I would imagine lots of newer players havn't boughten the older games. So my idea is for a future Duels game to have all of the decks from all previous games available, as long as you have bought them.
This would give guys like me who have lots of decks a massive boost, also people would go back and buy older DLC and core games, giving a big boost in sales to the devs.