i really havnt decided about the drop rate. my new favorite class, the monk ranger kills very very little as she is way too busy healing. so ill go through 90% of a mission and get one crusty little short sword or something equally useless. but then in the last bit i start to get an absolute ton of things.
granted i normally was killed and everyone else stole my loot (only on a couple missions, the worriors would let me tank...how nice of them...)
but in a way its nice, because if it was according to your thought then i would NEVER get anything sence i am a nurse (char named "The Nurse") first, and a ranger seccond when people do not need to be healed.