Mass Effect 3's "Extended Cut" DLC, which will expand on the ending, will be released on June 26th. Bioware PR has said the extended cut will "expand upon the events at the end of Mass Effect 3 through additional cinematic sequences and epilogue scenes" and will "include deeper insight to Commander Shepard's journey based on player choices during the war against the Reapers." However, Bioware has also noted that the extended cut will not fundamentally change the endings, but rather expand on the original ones.
As the endings will not be changed, I can't imagine that stretching them out would uplift them from their much-deserved rank of "worst endings in the history of the video game industry." Hopefully, this extension will mean the endings are less lazy and abrupt, have more differentiation than the color of the beam of light that rebounds throughout the galaxy, and make more sense than say, the ending of 2001: A Space Odyssey.
When we see the elongated endings for ourselves, we will either find our complaints put to rest and be satisfied with a series fully realized, or our anger will re-erupt as we find the extended endings are just as bad as the old ones. Here's hoping for the former.