The overall philosophy of Codex, especially the combat part, is to allow the player to partially manage the chaos of combat. The chaos is meant to always be there, it’s nigh impossible to fully eliminate that in almost any kind of real fight, but if you are skilled and use the right strategy, you can manage it so as to minimize your own risks and maximize the peril experienced by your opponent. This is how the tabletop RPG gets us closer to what a street fight or a good intense fencing match is like from my experience.
This is partially reflected by the core mechanic – the “Roll Many / Keep One” modified dice pool of the Martial Pool. I spent a lot of time looking at other systems – percentile base, conventional dice pool with target numbers, regular D20, D6, etc. etc. What I wanted was the widest possible variation in potential outcomes, without being enslaved to a flat probability curve the way you are in a percentile dice system. After doing the weapons encyclopedia for a Riddle of Steel book, I concluded that D10 or D12 dice pools offer too little variation. Everything had basically a DC 7 or 8, or else the system kind of breaks. A DC 9 means it almost never works while a DC 6 is a super weapon. Ultimately all the weapons become very similar.
With DnD it’s even worse of course, since the only way to differentiate a weapon is through damage.
A real fight has a wide range of possibility for any given moment, as wide as your perception and your imagination within the limits of the physical body. I felt that on a tabletop, where you are using physical dice, this was best reflected with a small number of D20s. It can’t be eight or ten of them like in a regular dice pool, because it’s too hard to ‘read’ that many 20 sided dice instantly. That is one of the reasons the Martial Pool is limited to four MP. This also matches Joachim Meyers admonition to make no more than four strikes in Krieg, because after that you are running out of ideas.
This 20 sided dice mechanic is used, as much as possible, with some consistency throughout the system. You always want to roll high. When there are ‘human complexity’ level probabilities involved, (like for a skill check) you use the wide variance of the D20 instead of a smaller die roll.
I think any ‘reforms’ should try to adhere to this philosophy, and try to be relatively consistent in how the dice are used. If that makes any sense.