Arelith

The way NWN treated the spell Premonition is, at best, lazy - it essentially takes a divination spell and turns it into an Epic Stoneskin, of sorts.

This is far away from the original spell it seemed to be based upon, which is Foresight. I'm pretty sure the script for Premonition could be altered to function similarly:

d20SRD wrote: This spell grants you a powerful sixth sense in relation to yourself or another. Once foresight is cast, you receive instantaneous warnings of impending danger or harm. You are never surprised or flat-footed. In addition, the spell gives you a general idea of what action you might take to best protect yourself and gives you a +2 insight bonus to AC and Reflex saves. This insight bonus is lost whenever you would lose a Dexterity bonus to AC.

Basically, in code, instead of the stoneskin effect, this spell would apply immunity to sneak attack, plus the applicable AC and Reflex save bonuses. In a MUD codebase I developed, I further added the effect of a perpetual Find Traps, though, unsure if that could be done in NWN without further gumming up the heartbeat script.

In any case, fortification against sneak attack in a spell would be IMO way more flavorful, and even useful, than "yet another damage reduction effect."