Hussar said:
Y'know, this one bugged me enough to pipe up.
If 2 inch spikes disturb your sense of space so much that you cannot stop yourself from bumping into walls constantly, I REALLY hope you never get a driver's license.
Snarkiness aside, I can see what you are trying to say, but its not the same as what I'm trying to convey. First, when you drive, you usually are looking where you're going and can have a rough three-dimensional guage of where your car is compared to other obstacles. While a car is not a living extension of your body, you can be trained to be decent at learning where it is in space around you. However, if you add on a trailer or a ton of crap on the top of your car you're hauling around, it severely impairs your ability to drive as you normally would, and you have to pay conscious attention to your driving more.
In addition, your muscles and joints have structures called golgi tendon organs, muscle spindles, and proprioceptors that give you feedback about the position of your limbs in space, and about how much tension is being generated in a given muscle or tendon. The sensory info coming from these three types of information combine in the cerebellum and sensorimotor cortex of your brain to give you an idea of where your body is in space. Numerous studies in exercise sports physiology have shown conclusively that altering the weight distribution across your body impedes your sense of proprioception and ability to maintain balance and coordination, and even after time to train and acclimate to the new load, you're at best at 80% of your normal capacity. This is why football pads and gear are streamlined to impede joint mobility the least, and are made of lightweight components with their weight distributed across your axis of balance so it doesn't throw off your center of gravity. Adding spikes to armor WOULD screw with this badly, and while real medieval armor wasn't the best about distributing weight, fantasy armor with spikes like that would severely hamper the mobility, balance, and kinesthetic senses of a fighter trying to use it. Your body works best when you follow the motor programming inherent in it, and the spiky armor would interefere with that- meaning you had to pay more conscious attention to your movements. Constantly having to make conscious adjustments to your movements always makes you less efficient at those movements, this reducing range and capability of motion, and reducing the effectiveness of the fighter.
Like I said earlier, some spikes on the breastplate or on forearms or greaves might be managable, but not on shoulders, elbows, or other highly mobile joints. The problem here is that you are biologically wired to know where your body is in space around you, and adding on extra bits of spikiness and dungeonpunkiness does mess with your ability to function at something even close to normal capacity, and studies have shown you can't be adequately trained to improve that ability. So again, it seems really stupid to go dungeonpunk when your survival is at stake. Would spikes be a good idea if they were practical against grappers- sure. But the problem is, they aren't. We can argue aesthetics of who likes vs. doesnt like spiky armor all day, but you can't argue the anatomy and physiology behind what really occurs.
In the end, it doesn't matter what I think about this issue for your game- if you want to allow spiky armor in your game, go for it. I just think it looks ridiculous and its been shown that it would be a severe impairment to any fighter who wore it for a number of biophysical reasons. To me, its one of those things that represents style over substance, but in an annoying way- much like the ultra-goth slant of the Vampire books in the 90's, we have dungeonpunk for D&D in the 2000's.