In general, I agree that writers should be free to determine how their stories end, regardless of reader reaction - of course, this comes with the caveat that readers are just as free to criticize perceived failures.
The problem with the Mass Effect 3 ending _specifically_ is that, of the three choices given to the player, two have already been invalidated by the games themselves, because they're associated with antagonists you've already defeated. If you choose Control, you're basically proving the Illusive Man right (this after spending a good five minutes arguing with him), whereas if you choose Synthesis, you're justifying everything Saren did in the first game, since that's what _he_ wanted too.
It's not the linearity of the ending that's frustrating people, it's that the ending itself offers no closure, no resolution, no specific details of the sort you'd expect from a BioWare game. Were there still millions of people on the Citadel when it exploded? The Council? All those refugees? Your former squadmates? How do characters in one location suddenly end up in another? How does that "magical space laser" do what it does? Granted, these are all relatively minor elements in the overall narrative, but for a series which has prided itself on attention to plot details, their omission here _is_ glaringly obvious.
The problem with the Mass Effect 3 ending _specifically_ is that, of the three choices given to the player, two have already been invalidated by the games themselves, because they're associated with antagonists you've already defeated. If you choose Control, you're basically proving the Illusive Man right (this after spending a good five minutes arguing with him), whereas if you choose Synthesis, you're justifying everything Saren did in the first game, since that's what _he_ wanted too.
It's not the linearity of the ending that's frustrating people, it's that the ending itself offers no closure, no resolution, no specific details of the sort you'd expect from a BioWare game. Were there still millions of people on the Citadel when it exploded? The Council? All those refugees? Your former squadmates? How do characters in one location suddenly end up in another? How does that "magical space laser" do what it does? Granted, these are all relatively minor elements in the overall narrative, but for a series which has prided itself on attention to plot details, their omission here _is_ glaringly obvious.