Introduce a solo gameplay mode to MTGA similar to what Hearthstone has with its "Solo Adventures".
Basically the puzzles of the colour challenge but more difficult and on a grander scale with storytelling involved.

This would be a great way for players to enjoy the lore of MTG and provide a fun game mode for solo gamer's and anyone who wants to play offline on mobile. You could have exclusive sleeves and cosmetics to go with it once completed.
I would buy this.