I'm thinking about using the wound variant/damage save mechanic from UA and am looking for some feedback from those who've used it in their D&D games. Are there any hidden pitfalls or problem areas that need to be addressed (like massive Fort saves, for example)?
After a few tweaks, I got it to work beautifully. Combat at low levels takes slightly longer as both the PCs and enemies tend to have more "hit points" but other than that, everything seems to work about the same. You were correct though, by the rules in UA, creatures with high Fortitude saves are near impossible to kill.
There are a few rough bits that I felt needed to be smoothed out. Here's what I changed:
Sneak Attacks: Sneak Attacks deal an amount of wound damage equal to the number of dice you roll. The extra damage goes to Vitality. For example: a 5th level rogue attacks a fighter with a sneak attack. He rolls 1d6(rapier)+3d6. The first three points of that damage goes to the fighter's Wounds points, the rest goes to his Vitality. A critical sneak attack is handled exactly the same way except the 1d6 from the rapier is also applied as Wound damage.
0 Wound Points: The Fortitude DC to determine if you are Disabled is 10 + negative points. For example, if you have 5 Wound points and then take 8 points of Wound damage, you roll a Fort save DC:13. If it was 12 points of damage, the Fort save would be DC:17.
Disabled: Everytime you take damage, it is applied to the DC of your Fortitude and you must roll again. For example, if you have 5 wound points, get hit for 8 points of wound damage, you must roll a fort save DC:13 as above. If you pass, you are Disabled. If, in the next round, you are struck for 7 points of damage, you must roll again but the Fortitude save is now DC:20.
Dying: The DC of the Fortitude save you must roll each round is 10 + negative points + 1 per round. For example, if your Wounds points have been reduced to 0 and you have sustained an additional 12 points of damage, the Fort save is DC:22 + 1 per round. Additional damage further increases the Fort save DC.
Heal Check: To upgrade a character's condition from Dying to Disabled, a character can perform a Heal check at the same DC of the Dying character's Fortitude checks. For example, if the Dying character is rolling his Fortitude against a DC of 12, then anyone trying to use the Heal skill on him likewise needs to roll against a DC of 12 to upgrade his friend to Disabled.
Stable Characters and Recovery: Every hour, a stable character must succeed on a Fortitude save (DC 10 + negative points +1 per hour after the first) to remain stable. If the character fails, he becomes Dying.
As above, the Heal DC to help is the same as the Fortitude save the victem needs to make to improve his condition.