So I've been kicking around stealing ideas from some other games and one thing that interests me greatly (I've only done a single, limited playtest) is the idea of using a dice pool system.
Instead of the core mechanic being d20 + modifiers >= DC, I'm thinking of going all-in using the Reflex System mechanic from TW:2013.
Basics are as follows:
1. Your DC (aka TN aka Target Number) is the controlling attribute (Str for melee attacks, Dex for ranged attacks, Int for Int-based skills, etc.) with the intent to roll less than the TN.
2. Modifiers will still add or subtract from the d20 roll.
3. Each set number of skill ranks will allow you to roll additional d20 dice when using that skill, picking the lowest of the rolls - combat would also be based upon adding skill ranks instead of using BAB.
4. A modified TN of 0 = instant success, 20 = instant failure.
5. The amount you beat the TN by is a margin of success that adds to the amount of your success. Additional dice in the pool that also beat the TN will add 2 to the margin of success.
6. AC will be just "AC bonus + modifiers" and will lower your TN.
7. Armor will also use DR - half of the base AC bonus and will be multiplied by the amount of your weapon's penetration and subtracted from total damage you cause.
8. Weapons will have a base damage of the average of the current damage and a penetration equivalent to the current critical bonus.
9. Hit points will be based solely on Str, Con, and size, and damage will be compared to multiples of the base hit points to determine wound effects (anything from a flesh wound that causes you to lose one from your dice pool, to shock, blood loss/instability, and even one shot-one kill effects).
10. A hit location system will be used (head, torso, 2 arms, 2 legs for bipeds).
11. Whole-body magic damage (fireball, etc.) will be half of what it currently is (e.g. a 6d6 fireball will now be 3d6).
Other than the obvious (completely changing the base mechanic), what issues does anyone see with implementing this system (my intent is that combat should be deadly and not entered into lightly).
I can provide an example of implementation after receiving initial feedback.