Seriously, this is so ridiculous.... Let me simply the ridiculousness of that argument.... Do you honestly think a 2 hour Mass Effect movie of ANY type, Shepard or no Shepard, could match the rich quality and experience of the Mass Effect game series? Seriously dude, how could a 2 hour movie even come close to portraying that experience.... The whole point is that they CAN'T because the experience of a video game and a movie are completely different, you interact with them differently, the effect of them is completely different.
So bearing that in mind, what things CAN a film draw on from the games, knowing they can't recreate them.... Universe, characters and story. Now, if you're looking at adapting these games and you KNOW you can't match the immersive nature of the game, and you need a damn good story for the movie, what do you do? Take the epic, grand scale story that WORKS from the game or do you try and make a completely different one? Sure every ME game is slightly varied, but let's be honest, it's not like it's a completely unique game to every single person, there are constants and a grand scope.... Humans are a new addition to the universe, from an alien point of view, we have humans trying to enter the council, we have a threat to the council that only a human knows about or is willing to stop, finishing with a human saving the galactic council. Then, if you include later ones, you have a human uniting a crew and uncovering a great threat, and then obviously saving earth in ME 3.
THAT is the most obvious, and interesting story, to tell in a film. Forgetting Shepard for the moment, would you want to see that story in a film?
Try and look at this from a 'what would make a good film perspective', because honestly, if you keep looking at it with the attitude of "How can this be the same experience of the game" you're going to be disappointed whatever they do.