I'm not defending the ending. I only brought it up as an example of what can happen when fans are led to believe that they have an influence on what happens in a story. Leigh Alexander wrote this over at Gamasutra and I believe it:
"One of my friends thought the name of the fan petition, "Retake Mass Effect," (a subversion of the game's own "Retake the Earth" marketing tagline) was particularly interesting -- "as if it ever belonged to them," he reflected. But if games really are the owned vision of a team of creators, then BioWare's first mistake was committing so fully to the fiction that it did.
If you promise your players agency and involvement, they are going to take it seriously. If you use every trick in your repertoire to immerse and engage, to create a sense of ownership, it seems you will need to consider the implications of those promises beyond how much downloadable content you can sell. " Source