Um... I never actually bothered to wiki up on the original ME3 story so... what exactly was the problem with that game?
I mean, I saw clips of it in passing; from what I gathered, it was "all in someone's imagination" or something like that.
And could someone explain how the new ending "fixed" the story?
The story ended in a very open way that invited the players themselves to decide what happened to the galaxy in
their game. People complained that there not being gigantic blow-out endings of varying outcomes, saying that all of their decisions throughout three games made no difference in the end because they were forced to choose one of three "colored endings", and then given a small "in the distant future" ending scene to roll the credits on.
People were also upset because they found the antagonist race's justifications for doing everything to be entirely stupid given what was learned through the trilogy - The Reapers show up and cull advanced civilizations from the galaxy to prevent them from creating robots that would destroy them. People claimed this was bullsh!t because you're able to make a robot civilization get along with an organic one. The problem is that the people somehow missed the fact that it's the entire point that we the players, along with Shepard, find it completely dumb, hence why Shepard is given the decision to change things. The Reapers were a solution to a problem that ignored the fact that humans are unpredictable, and they were made by a program from eons ago that didn't take that into account - hence the entire reason the player is given the "multicolored choice".
The "imagination thing" was a theory about how the main character was being brainwashed by the aliens into thinking he was doing the right things, or that it was all in a grievously-injured Commander Shepard's mind.
The problem is that people attributed that final, multicolored choice as the be all end all of everything, when it was really just one last choice in a trilogy completely built around choices. I think there was some inflated sense of importance in the player's choices, though, because Mass Effect was never really anywhere near as open as people seemed to attribute it with based on the reactions to the ending.
Everyone went to the same locations, fought many of the same foes, and had many of the same experiences. The only differences that were affected by choices were in character relationships, that's about it.
People also complained that the things that are shown leave many characters with unknown or horrible fates. One in particular is that the Mass Relays (that allowed for intergalactic travel) were destroyed in the process, which everyone says destroys the galaxies because in the ME2 DLC Arrival a Mass Relay is destroyed and goes supernova - destroying the entire solar system that relay was in. This was really odd, considering how nitpicky the fans were, that they didn't take notice of both the circumstances nor the destruction of the relays themselves that were different between Arrival and ME3's ending.
The "expanded ending" added some still images over a short narration that showed what happened in the galaxy due to your decisions, and actually revised the Relay's destruction (which was entirely retarded considering there was nothing wrong with them). It adds a little bit to help players still formulate their own ideas of what happened, but some people were still p!ssed that it wasn't a bunch of different and extremely varied cutscenes.
All in all, the ME3 ending was hated because people somehow lacked imaginations.