So, there’s another design diary up on WOTC’s site, and that means another chance for me to write an inchoate, off-the-cuff rant there, and then post it here, and pretend that it’s content.
I’m a bit confused as to how these lists are created. Firearms rules, for example, can be as simple as crossbow rules: They’re a weapon, they do damage, boom, done. They can also be complex, with rules for powder measuring, firing in damp conditions, wheellocks vs. matchlocks vs. flintlocks, etc. They’re an example of a concept or option that can be iterated through multiple levels of complexity.
The idea of “only one rules change at a time” is likely to frustrate those people most likely to want advanced rules, and it goes against the concept of modularity. If the core system is fine, then, grid based combat built on the core, and hit locations built on the core, work fine, because each replaces a different module — in programming terms, each is a subclass of a different root class. The grid rules that determine where you are and how this affects your chance to hit should not care what happens after you’re hit — if your armor is DR or if your hit location matters. If there are such effects, it is the “after hit” rules that should contain them, and inform the grid rules of what’s happened (“I’ve been hit in my legs, I’m at -5′ speed for 1d4 rounds.”) The grid rules only care about “your speed”, they don’t care if some other rule has modified it.
Likewise, if we use a spell point system, we can’t have hit locations? Why not? I really don’t see your underlying logic here, in terms of how you decide to wall off one section of rules from another, or decide you can only pick one option from column A, two from column B, and free egg roll if ordering for four or more.