I have an idea in terms of another aspect of shinigami that could be added:

We could have for those of high intelligences a place where they are allowed to have special devices; for example Urahara's Cloak that completely hides the wearer's reiatsu or even like Mayuri's super human drug. I guess what I'm suggesting is outside of the shinigami's normal abilities that being zanpakutou, fighting strength, and kido; w can have another section for inventions and then set a cap on how many inventions the shinigami can have. Tell me what everyone thinks of that idea. Naturally this is just a rough generalization, but if its well liked maybe something can be worked out.

hmm well we cap intel at 50 (along with Kidou so they add up to make the forbidden Kidou) but after that i'm thinking people could create their own Kidou and or inventions, thats a cool idea *nods*
i'll wait to se everyone elses thoguhts on it.... >.>