: http://forums.bungie.org/halo/archive32.pl?read=952875
: http://forums.bungie.org/halo/archive32.pl?read=952804

People can't possibly empathize with four-jawed lizard aliens, so the animators synced the jaws together and made the Elites look more human.

People can't get behind the idea of a heroic warrior that (legally!) sleeps with married women, so 343i wrote him as an explicitly monogamous husband. In fact, they made a point of it because it shows what an upstanding, moral person he is.

People can't possibly empathize with a female alien (How would the audience tell them apart from the males?) so 343i gave her hair and tits and fused her jaws together and devoted half of her on-screen time to helpless giggling.

People can't identify with aliens, so 343i did their best to turn them into humans.

And they call themselves writers.