Celebrim
Legend
AC simply is a horrid mechanic as implemented in the D&D/d20 lines...
Real world: Armor works by spreading the impact area so the force doesn't result in crossing the tissue damage thresholds (bruising, muscle disruption, bone fracture, bone cleaving.)
Yes, but AC models this by just by treating hits that don't cross the tissue damage thresholds as being another type of non-hit. In other words, we're modeling the end results and not the process. Yes, this is highly simplistic and abstract, but it doesn't necessarily result in something all that different than modelling the process except in edge cases. Process modelling doesn't necessarily result in more realistic end results, because the various steps of the process modelling will themselves have abstractions and simplifications and often the designer's sense of what is realistic is wrong resulting in really unrealistic outcomes.
GURPS is probably the definitive example of this. The ideas behind the process are informed by knowledge of reality, but the outcomes are not only not helpful to a game they don't even manage to be realistic.
Pheonix Command could obtain just about the same results by getting rid of all the tables and processes, and just use small amounts of hit points and weapons with large amounts of random damage with maybe one table for random non-lethal wound effects. All that process it engages in doesn't model even end up in reality, which is that death is caused by shock, blood loss, and infection.
Or consider even when you apply the process theory of "realism" to a game engine with a computer running it because the process is too complex to use by hand, such as in "Dwarf Fortress" where the system models layers of armor, skin, flesh and bone in an attempt to be "realistic". But the resulting combats are some of the least realistic and least interesting I've ever seen, to the point of being unintentional humor.