Whatever your feelings on this particular topic, you have to be impressed and heartened by the sheer humility shown by Bioware here: http://blog.bioware.com/2012/03/21/4108/
I don't know how in the hell they are going to address this with DLC, but it sounds like they'll try:
Exec Producer Casey Hudson and the team are hard at work on a number of game content initiatives that will help answer the questions, providing more clarity for those seeking further closure to their journey. You’ll hear more on this in April. We’re working hard to maintain the right balance between the artistic integrity of the original story while addressing the fan feedback we’ve received. This is in addition to our existing plan to continue providing new Mass Effect content and new full games, so rest assured that your journey in the Mass Effect universe can, and will, continue.