I've had this thought kicking around since I finished Mass Effect 3 and didn't want to discuss it for fear of spoiling things. But the science fiction trilogy concluded a while ago and I figure I ought to get these thoughts out before they slip beyond the horizon of cultural relevance.
You may recall a great deal of anger about the ending of Mass Effect. I'm sympathetic to people's frustrations but also to the designers' desire to end their franchise.
I think people approach stories (including story-heavy games) in two different ways. Some people are in it for the story and some people are in it for the world. People also care about the characters, but the way most writers make stories, characters fall into two types: story-characters (who undergo fundamental character changes across the narrative, like Luke Skywalker) and setting-characters (who remain basically consistent, like Captain Kirk). Most people don't analyze how they enjoy stories, but I see people gravitate toward one type of story or another based on their preferences, and I've seen people get all kinds of angry when their initial assumptions about the type of story they're experiencing don't pan out.
Mass Effect had that problem. People thought--and some of it was wishful thinking--that Mass Effect was about the Mass Effect setting, and that was a reasonable view to have, because the setting had so much in it: Cerberus and Reapers and the Council and biotics and the Presidium and space pirates and a million other things. And it came as a shock to a lot of people when they learned Mass Effect was really about a single story (Shepherd's decision) and a single theme (the old man vs. machine chestnut). Mass Effect was a game about something, and it also happened to have a universe attached to it. Mass Effect 3 dragged together most of the previous two game's plot elements, from the Genophage to EDI, and showed how they were all the same kind of story.
Mass Effect 3 didn't do a perfect job at that, which is part of the reason why a lot of people were mad: ME3 was far from perfect; its execution was often heavy-handed and clumsy, and it exposed the fundamentally linear nature of Bioware's stories, despite all the writers' attempts to hide that fact. But more importantly, ME3 took people's universe away.
The Star Wars "expanded universe" has been lurching along for almost 40 years now. Almost everything in the EU sucks, I mean, it's worse than bad, it's completely terrible and full of elements so tone-deaf that I wonder how they ever seemed like a good idea. But as a tabletop gamer, I've had an absolute blast running games in the Star Wars universe.
The Mass Effect universe is just as cool (I imagine a whiteboard at Bioware, Day 1 of New Science Fiction Game, with "Universe Just As Cool As Star Wars" written on it and underlined three times), but I won't ever play in that universe because the designers destroyed it. Now, I'm not all broken up about that, because I can build my own settings and there are plenty of ready-made ones, but if I were the sort of person who loved Mass Effect for the universe, ME3 would have been a kick in the junk. No more Omega, no more Alliance, no more permanently-unresolved stories about the Krogan vs. the Salarians or the dangerous Batarians and their hatred of humanity's success.
But...Some of these desires, I think, are toxic to creativity. The Genophage was interesting for 2 1/2 games; dragging out the angst interminably is what makes superhero comic books so unreadable. Ditto the Batarians. And I think it's naive to expect that the "real story" of Mass Effect is Shepherd and his/her friends fighting Batarian gangsters forever. We all knew ME was going to be more than that, and anyone who knew the first thing about science fiction could see in what direction the plot was going to go.
Further, I kind of respect the designers for blowing up the universe. "No, Mass Effect isn't a setting that gets played out forever, that gets cluttered up with fanfiction-level content after ten years, that slowly spawns an incomprehensible and labyrinthine continuity that alienates all but hardcore fans; Mass Effect is a story about one thing and when that one story is done, the curtains come down." It takes integrity to do that, and it takes a firm understanding of what your story is about.
It's just a shame that what Mass Effect was about was handled so clumsily. But that's an issue of game design, which is outside the scope of this undirected musing. I respect what Bioware tried to do, but I think that, in their attempt to close off the universe, they closed off the story too, and gave us a strangled whimper to conclude their narrative. I don't want to mess around in the Mass Effect universe forever, with the setting's dramas frozen in time for my eternal savoring, but I wanted more of a decision about how I brought down the curtains.