Would you mind giving us the method you use to calculate the Threat DC of a creature? Is a very interesting idea.
I think this is a complete system. I think I got all the numbers right so it works with the exact same probabilities as the present rules.
Normal player rolls (no change)
Attack Roll: Normal
Spell Casting Attack Roll against AC: Normal
Resist Spell Roll by Save: Normal
Resist Trap/Effect by Save: Normal
Players now rolling against the opponents' threat or spell attack, to impose their spell effect on target, or to impose their trap/effect on target:
Defense Roll. When the player is attacked by an opponent. DC equals 12 + attack bonus. Player’s bonus equals AC – 10. A natural 1 is a critical hit.
Spell Defense Roll by AC: When the player is attacked by an opponent's spell. DC = 12 + spellcasting modifier. Player's bonus equals AC -10. A natural 1 is a critical hit.
Spell Casting Effect Roll: When the player tries to impose a spell effect on a target. DC = 12 + save bonus. Player rolls d20 + (spellcasting modifier -2).
Trap/Effect Roll: When the player tries to impose a trap or other effect on a target. DC = 12 + save bonus. Player rolls d20 + (trap/effect DC - 10).
The last roll for Trap/Effect is for things like if a character uses a poisoned blade against a target. Instead of the target (e.g. the DM) rolling a saving throw against the poison's DC 15, the player would roll the poison's effectiveness/strength (DC 15 - 10 = +5) against the target's save DC (12 + save bonus). So, it the target has Con save +4, the DC for the player's roll would be 16. The player would roll d20 +5 with a total of 16 or better indicating the target is affected by the poison.
I'm sure if I missed anything, someone will tell me.
