AC comes from your armor.
There's that. I'm debating about physical stats. If I do them, I'm thinking I'll do just strength, dexterity, and wisdom.
EDIT: Actually, I changed my mind. There's this RP called "Bushido" that woul actually make this a lot simpler. Basically you get 60 points that you can assign to different skills. That number may change. Then you assign a certain amount of points to skills, like you could have 30 on sneaking and 30 on stabbing. Then you would have a 30% chance of sneaking past someone. On second thought, you would definitely have more than 60 points. And then probably physical attributes could be part of that.