IME, more bookeeping, even as simple as one extra stat to track, makes the game more complicated. As part of the core system, I believe they are trying to go as simple as possible. This may be too complicated for an entry level player. Also, for me, it sounds too much like the Star Wars system.
A specific point/critique I have is:
Every 10 hit points does 1 wound point, so a 25 hit point shot does 2 wound points which makes critical hits nastier, but 4 hit point shots do 0 wound points.
I think what you meant to say there was
"any single successful attack inflicting 10 or more hit points, also automatically does 1 wound point for every 10 hit points (10 to 19 hit points = 1 wound point, 20 to 29 hit points = 2 wound points, 30 to 39 hit points = 3 wound points, etc.)".
My critique is that this adds additional disparity to the system, and even more inequity between certain classes and characters.
A low hit point character will likely always lose all their hit points long before they incur enough wound points for death (figure average Con. score of 10, giving them 10 wound points, unless they have 100 or more hit points, they are almost always going to reach unconsciousness before suffering enough wound points to die).
A high hit point character probably has more of a 50/50 shot at whether they lose all hit points (uncconsciousness) or lose all wound points (death) first.
A high hit point character with a low Con is almost always going to die long before becoming unconscious.
I think it completely changes all expectations of how to survive combat, and makes these expectations inconsistent across different classes and builds.
The only way I can see to fix it would be to use percentages. Each character has their own wound threshold for hit points. Depending on how many wound points is the average would determines what percentage to use. Probably somewhere around 5% or 10%. So, whatever a characters total hit points are, their wound threshold would be 5% or 10% of their total hit points. Whenever they suffer that amount of hit point loss (different for every character) they lose a wound point.
For example: a character with 35 total hit points would have a wound threshold of 3 (10% would be 3.5, round down and you get 3 hit points). A character with 75 hit points would have a wound threshold of 7 (10% would be 7.5, round down to 7).
Of course though, this still runs into math inequities due to varying Constitution scores.
For equity you'd probably need to use a ratio of Constitution to Hit Points as the basis for each characters percentage, then use that percentage to determine the characters wound threshold. Which too me (and probably most other people), would be a completely unacceptable complication to the system.
IMO, all of the above and IMO the original concept also, are far to complicated for the basic core system, don't really "add" anything to the play experience, and create some significant problems with the systems math.
