The name says it all. I don't like playing games with privates who have only just finished their 4th game and are assigned a rank from that. I think that a new recruit should play 10 games, and then are given a more appropiate rank. The more games a player plays, the more accurate their rank becomes.
This will improve gameplay by telling players what type of person they are playing: for example a new recruit that has lost 4 games in a row is still a private (normally). A more accurate rank for such a player would be cook (at that time).