So BioWare has listened to what everyone has to say about the ending to Mass Effect 3 and have decided to do something about it. Now I know it is a bit late but I was on my way to PAX when this news dropped. What BioWare will do, sometime this summer, is release an Extended Cut DLC that will provide more closure to the events of Mass Effect 3. What does this mean exactly? Well it means that the ending will not be changing and Shepard will have to make the same choices at the games conclusion. BioWare had this to say about that-
Are there going to be more/different endings or ending DLCs in the future?What you are getting from the DLC is additional cinematics and epilogue scenes that will further expand on what happened at the end of Mass Effect 3. This may not be what everyone is expecting but we'll have to wait and see how these additional scenes change the ending. Is this the right move from BioWare? Who knows but it is something and that alone should keeps fans sedated until this summer.
No. BioWare strongly believes in the team’s artistic vision for the end of this arc of the Mass Effect franchise. The extended cut DLC will expand on the existing endings, but no further ending DLC is planned.