The survey (via GameSpot) is lengthy, and focuses on the layout, visuals, difficulty, and overall experience of each Firebase map. BioWare hasn't given details on the reasoning behind the survey, or whether this relates to future Mass Effect plans or changes to the current map sets. Reckoning was the last multiplayer DLC, and the sizable Citadel was said to be the final piece of planned DLC entirely. Shacknews has contacted BioWare regarding the survey.
Little is known about the next Mass Effect. We do know that BioWare Montreal is handling it, and it will run using the company's proprietary Frostbite 3 engine.