The title of this thread made me sad, but some of the comments cause me physical pain with how wrong they still are despite great stuff put out by people explaining everything. If you don't understand why the endings suck, watch and read the things in my signature. It's the best things I've found. And no, none of it is mine so it's not that I'm some genius.
But on the other hand, Shepard can duck most of those sacrifices through good gameplay. It isn't crazy for a player to end up thinking that ME is all about finding a way around the hard choices.
This isn't one of the posts I described above but I wanted to note it.
That's exactly what happens. It's not just good gameplay, it's good role play or the events of the story. The only hard choice you really have to make is Virmire. The Council choice was next to meaningless, as was the Rachni Queen. The Collector Base choice didn't matter and it's easy to have no casualties for the Suicide Mission. I guess you had to do several things right to get Peace in the Rannoch arc. Mordin or Padok Wiks sacrifice themselves so that's not on Shepard. The series was often about finding the third option or fixing problems, so the fact that Shepard couldn't do this at the end was an issue. And no, I don't mean Synthesis. I mean telling the Catalyst to cram it and laying out how things are going to go down because the Catalyst is wrong.
Mass Effect does not end with Shepard winning the day and riding off with his lady love (or man love depending) into the sunset. Bioware takes the notion of total war very seriously, and the story is as grim as it is engaging. Victory is possible, but not without heavy loss and the total alteration of the status quo. The game can end in several ways, depending on how you play. Even the best victory scenario comes at a price, resulting in the death of friends and allies. In Mass Effect, as in life, you cannot always get what you want and you have to make the best with the options you have, even when those options are not good.
The end also is not straight forward, no matter what scenario plays out. The entire end of the game appears to be an exploration of the human mind. Bioware has taken a page, it seems, from Inception, making it unclear what exactly is “real” what and isn’t. It’s surreal, unsettling, and makes you THINK about what is happening and why. It makes you consider every choice you have made up to this point in the series (one of the clever aspects of the series is that Bioware allows you to import your Shepard from one game to the next, coming with all the choices you have made, good, bad and ugly. Shepard always has baggage.) It makes you question your own assumptions and motives on several fronts, and how you deal with that impacts your final choices.
You do not come away from the end feeling happy. It is, regardless of what you do, a visceral punch to the gut, punctuated with the smallest ray of hope – a ray that is only there if you made particular choices through the series.
Some rabid fans of the game do not like this. They have started web petitions, written blogs, made Youtube videos all about how the end of ME3 “sucks”. There is not typical, flashy, shoot out with a final enemy to win the day. There is no triumphant hero pumping his fist in the air in victory. There is no simplistic, action movie, final moments. You are left instead, to think long and hard about what just happened and why
What Bioware has done is craft an ending one has to deeply consider and interpret, a very rare feat in a medium that is still maturing into a full blown art form: Did Shepard really defeat the Reapers? If so, how much of what we saw was “real” and not just in his head? The end offers up more questions and it does answers.
Rather than change the ending, my hope is that Bioware will do what it has always done – offer up downloaded additions to the game that expand the universe and lead us in new direction. But change the ending because some players have an over the top, fanboy meltdowns over it? No. We shouldn’t be asking to be spoon fed base pap. There is a legion of sitcoms and awful science fiction programing and lunk headed fighting games for one to delve into if you want that. What Bioware has created is something unique, that should be allowed to stand and players should learn that it is ok to have to think. The low common denominator they appear to ask for isn’t worth it.
They really don't take it all that seriously. They have you "take Earth back" because you, the player, are human, not because Earth has some ME universal significance. You mostly can get everything. You can get both Quarians and Geth. You can save the Genophage and still get Salarian support later. You don't need all the possible EMS and EMS is just a score that affects things in unclear ways with no differentiation despite being split into categories. Better get all those ground troops to fight 2km tall space ships! It wasn't about taking the best of bad options. That would have been pretty dark and a different series. Sitting here now, I'd love to play something like that, though I wonder if I'd hate it if I actually did. 
If you're right that Bioware tried to borrow from Inception, that's a glaring example of why the endings don't work. The ending of Inception fit the events of the entire rest of the movie. You can't just shove that into a different story that wasn't dealing with those issues and expect it to work. The shift in tone and pacing after the beam run was jarring. Indoctrination was never something that was nailed down because it was always something that was happening to other people which we mostly saw the end result of. We saw enough to piece a lot together, but we never experienced it first hand.
There is no depth to the endings other than what you've invented in your own mind to defend them. They are a shallow mish-mash of ideas from other stories that don't fit. More on that in response to the next post. The endings didn't make me think; they made me wonder what the hell the writer's were thinking.
Of course, there are some people who played Mass Effect 3 only for the characters or as a "romance simulator". So they completely ignore the Reaper story, and when the ending originally came, there was no closure for them. Those people don't believe the Reapers are the central point of the story, but rather the characters and their own personal conflicts which weren't resolved at the end initially.
As in they didn't tell you what happened to everyone after the game, but they tell you enough during the game to give you that sense of closure. Jacob says he's going to be a father, have a kid named Shepard. That's just one example.
The game that they were sold was a galactic war against the Reapers. Not as a dating simulator or story which solely revolves around character interactions. It does wrap up the Reaper story as promised though.
This right here is why you don't get it. While you might have been right about ME1, starting with Mass Effect 2 the series became about the characters. The Reaper conflict was almost absent from Mass Effect 2 and the main plot was trash. However, Bioware wrote far superior stories for most of the characters and gave them a lot more personality and screen time. The war become the events going on in these characters' lives: the challenge they had to overcome. Tuchanka matters because of Wrex and Mordin. Rannoch matters because of Tali and Legion.
And yet the characters were completely dumped from the ending. In a series and a game entirely devoted to gaining friends and forging alliances, Shepard is on the Citadel making the final choice alone. You had squadmates around for all the other decisions and they gave input, even if it was just binary to frame the choice. This has nothing to do with "romance simulator." That is another issue entirely. This is about Mass Effect being a character focused series.
The same is true of Star Wars. Your comment is the same as saying the character interactions didn't matter much as the space battle. It's the exact opposite. The Emperor dying isn't nearly as important as Luke's defiance and Vader's redemption. This is why we don't question how killing the Emperor saves the day when the Empire is still huge and powerful.