Alright, let me tell you what I know.
First of all, the rank system does make sense, BUT IT IS VERY COMPLICATED.
SOCOM is a competitve game (but you all knew that). That means to be successfull, you (you and your team) have to win games (I'm sure that's common sense as well). That's the main point. You have to win, and contribute to that win.
But there are two ways to win. Either kill all your enemies, or complete the primary objective. While killing your enemies will help, completing the primary objective will help you more. As you all should know there are a few different types of games. SUPRESSION (in which case the prim obj. is to kill your enemies) - BREACH - ESCORT -EXTRACTION - DEMOLITION.
People say that when you are a terrorist your rank goes up more because the SEALs have better weapons. WRONG. The reason that as a terorist you benefit more, is because most of the time your primary objective is to kill all SEALs. For example, in a breach game the seals have to blow up a terrorist target. The terrorists have to kill all the seals. If you played SOCOM II for a while, you should know that most games, no mater what type, result in either one of the team's deaths. So even if you as a SEAL kill all the terrorists 6-0 in a breachmap, you will not benefit as much as the terrorists would have if they would have killed you 6-0. This is because your primary objective is to destory a target, and theirs is to kill you.
Second, another key issue is WHO you play WITH and AGAINST. The ranks of both teams are summed up as a score, and compared to each other to see who is supposed to win. All this means is that eight ensigns will get a higher percentage increase if they win against eight captains. Whereby if the captains win 6-0, with 0 deaths, their rank will not change by much. I am sure most of you have noticed this.
http://www.playstationmagazine.com/a...86748%2C00.asp - this is a little article that gives you some info on the subject