I really hope that one day, multiple teams could be implemented, not only PHALANX's and Alien's. The more the actors on a map, the more of corpses at the end.
But right now, the feeling of immersion (for the few who are sensible!) could be improved by adding to maps some statics featuring corpses and gore, especially on city maps (allegedly more populated). For instance, on the Lab map, add a few dead security guards, etc. The same for wrecked versions of cars. This would "only" imply to modify the maps, I think.
Later, as an intermediate measure, a "team" of corpses could be dynamically added upon entering a mission (I don't know if this is currently possible, though). This would allow the number of corpses to be dependent not only on the mission's type (Harvest and Terror would be more gruesome), but also on population density (as defined by the mission's location), or even on the number of days the mission is available for. This shouldn't impact game flow much, as those people would be dead already.
