Wondering a bit about that too. Was my favourite DLC, the only one where they actually tried to evolve the gameplay (and IMO succeeded). Warden's Keep was decent, Shale as well (but as a partof project 10 $ and thus essentially a part of the main game, and the discussion around it's DLC role is... mostly academic), but ostagar, golems etc. were simply not very good, and looked pretty obviously very low-budget. Awakening still confuses me, in a lot of ways I think that it's better than the main game, but it's also even more lacking in polish than said main game was.
Well, I dunno, Shadow Broker plays a relatively important role in ME1, a crucial role in the ME1->ME2 comic storyline, and by the looks of it, sets up the scene for a critical point/twist in ME3... I was no liaramancer, but I found the story aspects of it quite interesting, as well.