I feel a team writing for an RPG should be well-versed in the use of tropes and archetypes. They're inescapable, so they may as well be used well. Tropes I particularly like are gender reversal (we hardly see genuine female representation in games), decent use of innuendo, competently constructed composite characters, new twists on old stories (extremely difficult as every critic always says "it's been done" because there are no more twists), etc.