I, for one, would like more games where I get to play as the hideous alien and slaughter puny humans. I want to be the extraterrestrial monster with facial tentacles and techno-organic death rays and a thirst for the blood of homo sapiens! Satisfy me, video games industry, or else I will command my fleshy minions from outer space to drain your bone marrow!
Anyhow, I find that there is one thing missing in all these grizzled video-game space marines that is present in all the best space cowboys: snark. Consider the characters of James Kirk, Han Solo, and Mal Reynolds (the Triumvirate of Captain Tightpants). They're rough, tough, and they fear no danger, but they're also very witty. They've got swagger, they're as quick with a one-liner as they are with their pistols, they never let themselves get bogged down with angst, and they can be quite charming and even gentle when the occasion calls for it. Does Master Chief do these things? Do any space marines do these things?