I'm excited for this as well and I hope this DLC answers A LOT of questions. But I hope some people realize that many people have issues with this game and they have nothing to do with the endings. These issues can't be fixed for ME 3 but hopefully for future installments.
1) ME 3 is the most linear Mass Effect yet which affects it's replay value. ME 1 gave the players the choice to pick a planet out of four and piece together each storyline. ME 2 was all about recruitment and we can recruit in any order for each of the 2 waves of dossiers. ME 3 follows the first one in terms of having most of our team at the start so why not give us a choice for the story paths? Would disc swapping for the Xbox version be that much of an issue?
We could have a choice between Rannoch and Palaven after doing the Mars mission. From there we go back to the Citadel, then Thessia opens up, and once all 3 race storylines are complete, Sanctuary becomes available. Change a few minor story details (Such as Kai Leng getting the Prothean VI on Thessia, that plot could happen after finishing the 3 race storylines on another Asari planet) and we could have had a more open ME 3. I've only beaten the game 3 times using 2 out of the 6 Shepards imported because as soon as I hit Tuchanka, I have to stop playing.
2) Too many fetch quests, not enough actual fun quests such as the Aria questline. Having more than one quest hub could have solved this but then again it would have obviously pushed the game back. The Quarian Fleet or Surkesh could have had a small hub with shops and quests which could have added some flavor.
3) Insanity is a joke for ME 3. While it made ME 2 tougher yet more fun, Insanity this time around is almost the same game, except for Grissom Academy and the occasional grenade. Another factor for replay value.
4) The Earth Mission is a disappointment compared to the Collector Base from ME 2. The Collector Base is easily one of the greatest final missions in a video game ever so you would think that the next game would follow up with something as epic. In ME 2, if the player has done everyone's loyalty mission correctly, scanned enough planets to upgrade the ship fully, rushed immediately to the base to save Kelly Chambers and crew and assigned the right people for the jobs, then you get the everyone out alive and feel damn proud of yourself. Throw in the epic music and an actual boss and you have this masterpiece of a finale that even surpassed Illos/Citadel from ME 1.
While it was great to talk to our old crew members on the holocom, why couldn't we see them during the mission and help us out during some tight spots? There are leaked dialogues on youtube of them in combat on Earth so it seems that this idea was being developed in some form. Was it the evil deadline that made them scrap this? And we could have assigned the current squadmates not being used for reinforcements and use all of those war assests that we got to support them to ensure their survival at the end.
These things could have made the Earth mission more memorable and fun and could easily push for more playthroughs for the players who dread the game after the 2nd or 3rd time. The Collector Base's hidden gem was all of the outcomes and failures that could have occured which gave the mission alone huge replay value.
5) There's no need to discuss the other major issues with the game since there are hundreds of topics about them already (day 1 dlc being an important subplot, forced multiplayer for the "best ending", Tali's face, etc). The only thing I can say about the ending DLC is that once again I hope it clarifies some of the major issues and contradictions of the endings. I am grateful that Bioware went ahead and gathered everyone to fix this huge issue and let's hope Mass Effect can shine again.