So what exactly are you going for? You mention "stats" several times, but what relevance does it bear to the actual RP? Are you saying that the RP itself actually uses stats or are you talking about the power capabilities of the characters in terms of their own canons?
Stats actually limit what a character can do, as a rough estimate when the players are writing in the character's actions. As it is, it does play a role in the RP.
For example, LN characters have absurdly high mathematical skills, that they can become engineers and architects even if they don't have a college degree (because they are past mastery) Suikoden characters are charismatic, thus people under them will listen better than people under Grand Chase characters will. MM girls can take a beating (Getting caught in an avalanche, trapped in a burning castle, shredded by a flurry of arrows, etc..) without any worse for wear that other characters can't.
The stats are compared to the denizens of the RP's world. E-- is the lowest and is below that of the world's population. E is the world's average citizen. It's like you're comparing a Koei Special Officer against a peasant.
Stats change with character growth. It can increase, or decrease. It may be permanent, or temporary. Stats define what a character can do and also acts like a guide, because certain actions require certain levels.