Previous incarnations of MTG: Duels of the Planeswalkers have enjoyed a fair amount of DLC, and Duels 2013 will certainly be receiving a similar treatment. All you planeswalkers out there might be happy to know that it will be getting a substantial amount of content, including new decks, challenges, levels, and unlockables.
Word has it that the DLC will include 5 new two-color decks, one for each of the Azorius, Golgari, Izzet, Rakdos, and Selesnya guilds. It will also offer new character portraits and achievements/trophies to unlock. On the non co-op side of things, it will add 5 single-player campaign levels and 5 single-player revenge levels. On top of it, another 5 challenge levels will be added as well. Sounds like this DLC should just be called All Things 5.
MTG: Duels of the Planeswalkers 2013 is currently out on PSN, XBLA, PC, and iPad with 2-player co-op.