That was ridiculous, you can't sue an author/publisher if you don't like their story, what do they think was advertised other than a conclusion to the trilogy? I don't understand what people were expecting in the ending, it was always going to come down to a few choices, It's probably prohibitively expensive to write a narrative open-ended enough to account for Shepard's decision to take up gardening on Eden Prime or whatever people wanted instead of killing the Reapers, almost all games with a tree of decisions are going to look more like a diamond - branching out and then collapsing back to a few possibilities

As an example, the Fallout 76 situation was different and worse - if you bought the deluxe version or whatever they call it, you were promised a canvas bag, and many people got a cheaper nylon bag, that is a better case for a suit