Design you own RPG?

[Senkusha]

I've been poking around various table top role playing gaming systems, and it got me to thinking, if you could design your own game system, what kinds of mechanics would design?  And because this is an anime forum, if you were to design your own anime-centric system, what things would you include?  I'm thinking of things like tropes too.  Let's start a conversation about this, and maybe we can create our own collaborative gaming system right here?!