I agree to an extent, but that's what covers are for; attracting the guy who buys games simply by passing by them in the store, finds the cover cool, maybe looks at the rest of the box, and then decides if he wants it or not. It's not meant to attract the kind of people who spends time in video game forums, keep tabs on potential purchases, and analyzes them in depth after playing (such as you, Sea). And as you said, it's not representative of the final product. I would never buy a Modern Warfare game, but Human Revolution is my 2011 GOTY, with TW2 firmly in second place, and Mass Effect 3 is my number 1 purchase of 2012. I don't like their covers (the 360 one in TW2' case), but I don't care either.
Also, while ''normal'' editions have this, usually Collector's Editions have better covers. ME2 has a scowling Shepard and thr requisite alian and hot girl, while the Collector's Edition has a broken piece of N7 armor in the rain. Much better, because it's more targetted at the fans who are usually better versed in that sort of thing.
Plus, I don't se what the ME1 cover is doing here. Shepard is not scowling or holding a weapon, the box art has three other major characters in prominent display, along with the Normandy and the game's Big Bad and an assortment of mooks. It looks more like a film poster than anything. And I like Crysis 2's cover, so there.