[Tangent]
Regarding genetical algorithms, I personally tend to favor Differential Evolution over anything fancier. Reasons being that it is simple, easy to program and does not need fancy mathematics, and, in the end, simply works. Adding a local optimizer like Conjugate Gradients or Newton's iteration will act as "brains". The other (though less stabile) algorithm I came fond of is SPSA, again due to simplicity and because it is quite easy to program.
Most likely, anything fancier algorithms simply take longer to program (less time to optimize) and also tend to be more error prone, while offering not so much performance improvements to make them worthwile. Or at least in my cases.
[/Tangent]
Speaking of body armor, I meant that there has been a lot of time available for evolution in the world, and it seems that the most carnivorous animals (that most likely also fight and receive injuries) do not have armor, but rely instead on mobility or on surprise. I don't know if this is relevant, but same applied when Mongols invaded half the Europe. They simply had a better bow and relied on mobility, while Europeans were stuck inside city walls.
I didn't mean that the body armor is useless or not worthwile. The thing has probably saved countless of lives, and even I were lucky to wear one in the army - during winter, that is. But it does have its limitations. While body armors develop, I'm wonder when we are starting to see lead tipped or depleted uranium tipped bullets in the service - or some other fancy stuff like extremely pointy drilling heads. If that doesn't work make that 7.62 mm rifle a 9 mm rifle. The other guy has to carry more armor if he wants to stop the bullets, and most likely the weight increase by bullets and larger rifle is less than the thicker armor needed to stop them. Also, shock experienced by getting hit by a bullet while wearing armor is also something. While the soldier most likely stays alive, he stops for a while.
Depends actually on what is being done. If it is attack, heavy armor is a problem. If patrolling and keeping peace (where mobility is not required that much), why not?
Mika