It's pretty close minded to assume that story has to involve a ton of cutscene. Mission dialogue from ghost, Vanguard, Eris, or whoever woks just fine. For example, the House of Wolves DLC did a pretty decent job of touching on the subjects of Fallen history and the Reef Wars through just this kind of dialogue. Secondly, they could have placed the cards in the actual game for players to read (or better yet, listen to them) if they want to in the game. Thirdly, even if they did it through cutscenes, it doesn't have to be overboard. For example, almost everyone agrees that Mass Effect 2 had a good story, and no one says it had too many cutscenes.