I find so many arguments, especially against multiple character races, so very selective. Why is it harder to make a game for a blue/green woman, or a "whatever from planet ego"? Yes, it requires some discipline in writing the thing, but it is the writing that dictates if it has to be any difference at all.
In ME1-3 has humanity been among alien races for some time. Even if Andromeda is before ME1-3 is it still many aliens that can have been living on earth and many humans that can have been born and raised in other non-human cultures. Meaning that the characters can have identical background regardless of race. Not so different from men and women having the same background story despite the differences.
Some of you that argue against this doesn't consider creativity, rationality and how to structure a story. Yes, if you take many stories and suddenly change the main character into something else, then the story might seem weird and surreal. It is nothing wrong with that if the story never was designed to handle it. But if you're willing to shape the story to make it plausible and coherent, then it doesn't have to be any difference at all (other than the player's head-canon and the player's different associations that is shaped by the choice of race, gender and appearance).
I seriously think you underestimate the writers if you think they can't handle that.
That said, perhaps the story is written in "stone" and that the whole game is based upon this story. That is however a choice and not meaning it would be impossible to have written a different story.