Responding to your edit.
Currently there is no "chance" in combat at all.
If you are in range, the target is in your swing arc, you hit 100% of the time. Parry can happen based on if the player correctly does a parry the direction you are attacking. So if you are attacking as an overhead attack, the parry person would have to parry overhead to parry 100%. More they are off from there (like parrying low) they take more damage.
The only way I could see the possibly of chance coming into play is due to desync/lag where you might not be in range, or the target is not really in front of you due to this desync/lag.
Then again, it's not really chance because either they are there or not, it's really not a random to hit roll or anything like that.
Having played Darkfall myself I can't see how a player from that game and playing it as long as you have would even suggest removing all player skill to make the game better. There is not a lot going for the Xsyon combat system, and removing that would make it so there pretty much is no combat system at all.