I don't think it would be a great movie but instead just a good popcorn flick...probably a bit like Expendables In Space
. If that even. I can't think of the last game-turned-movie that was any good at all.
If any film was to follow the games imagine the noise that fans would make about any decision the film Shep would make...even selecting the gender of the film Shep would see a bunch of complaining no doubt.