Imp said:This. Not that this distinction gets much play around here. I like second wind mechanics – beats the omnipresent clergy by a mile – but heroes should get meaningfully hurt from time to time.
The problem is "meaningfully hurt" is hard to do without making the character suck for a length of time sufficient to remove a fair bit of fun for the player. Whether it's a persistent penalty to rolls or a temporarily lower maximum hp total or some other drawback, all a grievous wound does is one of two things:
1) If time is not a factor, it causes the party to retreat and rest for as long as it takes to heal the grievous wound, in which case the rule has accomplished nothing but slowing down the story a little bit.
2) If time is a factor, the grievously-wounded character is forced to suck for several encounters until the adventure is over and the party can take some down-time.
Neither of those options, IMHO, is a desirable one. Also, from a game-design perspective, if you can assume that the players will enter most fights operating at full capacity, and "full capacity" is a very tightly-defined range (as, for example, with 4E's fixed hp and uniform check bonus), it becomes much easier to predict what kind of foes the party can effectively face. Personally, I'd rather have solidly consistent challenge levels in battles than a persistent wound system, and that's why I treat hit points and injuries "John McClane" style as described in my previous post.