Mass Effect doesn't show a single hint of self-recognition for how cheesy and cliche driven it is. If it's not serious business, it at least thinks it is. It's not even that cheesy. If you want to look at something that really is supposed to be that way, look at Duke Nukem or large parts of Fallout. There's no sense of it laughing at itself.
If it really wanted to drive the B movie Space Opera point home, it'd have a gangster planet or guys wearing capes. It seems more like it's trying to be Wrath of Khan, just without any of the depth.