I'm an avid fan of realism, and it was through games that I became more enamored with the science of how things really worked.
I couldn't stay away long, and having grown up writing about RPGs I guess I can't stay away forever.
Damage Theory. Right now, I'm collecting data about Damage. I got to enjoy and experience a lot of physics in air-soft. Reading up on books that deal with accuracy in air-soft guns, it was a natural progress when I began to look at books relating the physics of real guns.
What I found that any game designer could use is a Table of Forces, Mechanism (edge, piercing, weapon diameter etc.) as well as simple formulas of how much these forces diminish over distance. Information about Guns is not that hard to get. Information about ballistics is a bit harder, especially since there is trade craft involved.
Nat Geo's Fight Science is a great source for numbers, regarding forces certain bodies are capable of generating. Of course, I would be sure to keep this article in mind (Fight Science Bad Science). I'll try to get the Weight of the Performers or at least a making the assumptions clear if I can't find data on their weight, height and age. Also I will try to apply the Force to Weight Ratio the physics experts were asking for.
ARMA will also be a great source of information when performance moves to more and more weapons. After accumulating the data, it would be a simple task for any game designer to make their own abstractions based on the core principles they illustrate.
As for me, I still think Wound Saves (Aka Damage Saves) are still the fastest and illustrative way to handle it. Especially since HP systems are thoroughly debunk with this level of detail.
Practical Reason why i'm doing this? Other than the Ammo and Gun Debates I frequently see, understanding how fragile or resilient the human body helps in performance management. The more information I gain from this, the more I learn to be careful or what out for dangers. Like any physics lessons, understanding the principles gives some ability to act on the information not just idly sit by when certain things are happening.
From knowing what cover is best against an explosion, a hail of bullets, or from a racing automobile to knowing how much force is needed to/or avoid incapacitation or injury. How much damage throwing a piece of rock can deal, how much force can a tensed torso of Xlb male can take without injury etc. etc.
A collection of Rules of thumbs, and sources. Also a great way to exercise my very rusty math skills.
Other Things to Post.
Got Small Wars Manual and Combat Leader's Field guide. The best way I know to learn all of this is through an RPG where players will need the data of the book. At least understand why each procedure is important. Using Tactical and Management Manuals for RPGs is a great precedent for learning to learn anything useful through a very fun process.