heh, in one of my experiments for my Stonehall mod, I was playing with my spider-man-like aranea and some of my other races...
Due to random size differences, my (snake-man-like) lamia was considered smaller than the female aranea, so all her attempts to constrict her opponent failed. I was taking control of the lamia until I just got bored. Her tail slams, which relied on her quite large tail, however, were powerful enough to damage both lungs, the heart, pancreas, guts, stomach (vomitted three times a turn), liver, and several other important organs. The aranea was flashing red "+", which seemed to imply she was going down for the count.
The aranea, on the other hand, would keep trying to bite, but was incapable of doing anything but "glancing away" with its bite attack (which had paralytic venom). After about a thousand attacks, nothing so much as dented the skin. Surprisingly, the webbing attack, which didn't even have thickweb, would incapacitate the lamia whenever it was used.
I eventually got bored of waiting for the aranea to just freakin' die of all the internal organ injuries that the aranea had suffered, and went back to arena mode... and the aranea won the fight, in spite of vomitting roughly 140 times a minute (which really shouldn't happen on several levels), and in spite of not being able to break the skin in any way. I presume this occured because the aranea finally figured out how to grapple, and just strangled the lamia to death, which seems to be the ONLY way an unarmed creature gets kills without modifying teeth to be sharp or something.
In short, the core problem is that combat is utterly broken right now - even massive internal organ failure means nothing, and you can repeatedly "shatter" a skull without the skull ever actually ceasing to function. Death only occurs by brain death, blood loss, asphyxiation, torso seperation, or extreme temperatures. Blunt attacks do not cause bleeding, not even internal bleeding, not even when you significantly and repeatedly damage the heart, making the combat system fairly broken from a hardcoded standpoint, which means you're probably not going to "balance" this game's combat without making all attacks basically the exact same attack (probably just copying code off of an axe).