User blog comment:LilyheartsLightning/Citadel and Reckoning DLC announced/@comment-1786741-20130221185148/@comment-24174486-20130221194324

"They actually felt like they were adding to the story, not just doing things that seemed like they should have been in the main game."

ME2's DLCs were good, but with the exception of Arrival and LotSB, they didn't add much to the story but were small, self-contained side stories.

ME3's DLCs connect to the main story without being essential to understanding the story. From Ashes and Leviathan provided a wealth of insight into the history of the galaxy. Even Omega held greater plot relevance than most of ME2's DLCs—helping Aria would secure resources for the Crucible and the final battle—and it was just as implied in the base game as LotSB was.