With the amount of post-launch updates Bioware is coming out with, it almost seems like they forgot to finish making the game before release. They already have plans to release an extended version of the much maligned ending and a fix for the inability to import your Shepard character from previous Mass Effect games.
The latest update comes in the form of a free DLC called Mass Effect Resurgence Pack, that includes multiplayer maps, new characters, and new weapons. This is not something that players have really complained about, but I do think there should have been more maps for multiplayer.
The new maps are "Firebase Condor" and "Firebase Hydra". Condor takes place on one of Palaven's moons, and Hydra takes you to an abandoned Quarian colony.
The largest addition to this pack will be the inclusion of 6 new characters. In multiplayer, you will now be able to fight as an Asari Adept, Krogan Vanguard, Batarian Soldier, Batarian Sentinel, Geth Engineer, and Geth Infiltrator. The introduction of the Geth as playable characters is perhaps the most interesting, given that they were previously only featured in the game as enemies, not playable characters.
New guns include the Striker Assault Rifle, Kishock Harpoon Gun, and Geth Plasma SMG. In addition, new one mission use consumable merchandise will be available for in-game pack purchases. These include the Strength Enhancer (Applies melee damage boost), Targeting VI (Headshot damage boost), Stabilization Module (Weapon stabilization), and Shield Power Cells (Shortens shield recharge time).
The Resurgence Pack is available for free on XBox Live, Playstation Network and Origin beginning April 10.