Regarding SPESS MAHREENS, i have to say: "tropes are not bad". While Starcraft's and Warhammer's space marines do in fact look bulky, ridiculous, and overcompensatory, Mass Effect is an example of futuristic infantry done right: their suits are hardly bigger than today's body armour, guns are made folding, and they are trained military professionals (as opposed to religious fanatics or redneck convicts).
But really, i am only defending SPESS MAHREENS here because the alternative - Modern Warfare 2 and it's ilk with plots ripped from today's headlines - is much worse. And i like science fiction more than fantasy.
Now, regarding originality... the game industry is notoriously risk-averse. Making games costs a whole LOT of money, and something popular will sell easier than a completely original IP. If you want originality in the form of fresh gameplay ideas and totally-out-there settings, look for it on the indie scene.
And now, my suggestion for a fresh, yet familiar game that could probably sell well. For example, let's drift only a slight bit away from Mass Effect and imagine the following: a third-person shooter about a squad of badass space cops. You can play as a human or as one of several alien types (all of which are written in detail), use a wide spectrum of special powers in addition to standard guns, and your ultimate goal is to take down a major arms dealer. The powered armour is light like in ME, or even lighter. It's not entirely original, but it is pretty fresh. Would anyone play that?
