I've always like the idea of the Wounded disadvantage, but it seems so unlikely to come up in play.
Foes that know of your weak point can target it at -7. So, basically, foes who know you with skill levels high enough to absorb a -7 can attempt to hit your weak point. At -7, they could also just go for skull (-7), neck (-5), chinks in armor (-8), eyes (-9) - it's not a big stretch to hit something that is weak on everyone.
What seems like a throwaway side penalty is probably the main part - poisons treating skin contact as internal contact on that point. Which is kind of odd to me - so it has to be a wound, not an injury.
In a DF/DFRPG game, a wound is going to be covered by armor most of the time, hard to spot with Per rolls, and rarely vulnerable.
So it seems a bit . . . weak. Less restrictive and less punishing than even other 5-point disadvantages. It should come up more often than "the poison doesn't affect you, unless it gets inside the armor on your knee!"
It is only a -5 disad, so if I want to make it a little more harsh I have to be very careful.
Here is what I did:
As written, but add this sentence after the line ending "(round up)" and before the line beginning "Any poison":
Foes can sometimes strike this randomly - any critical hit to the location of your wound automatically hits the wounded area, in addition to any normal effects of the critical hit!
* * *
And done. That seems fair enough - sometimes when a random ghoul or ravenous ghost-bear or orc takes a slash at your neck they hit your old wound. But it's rare enough that it's not pushing a -5 disad up to something too harsh for the points you get.
Another approach would be to make it much more often - any critical hit, and 1 in 6 chance on any hit, period. For something like that, you'd want to make it -10 points, or remove the poison effect. That would allow for injuries (like a knee with a torn miniscus, or a bad shoulder, or separated abdominal muscles, or something like that) that don't have any obvious, open access to your bloodstream.