Heya again,
On our server, Time Stop is 1d4+1 rounds compared to standard 9 seconds of NWN. While this change is according to PnP, PnP has additional very heavy limitations to what can be done during Time Stop.
As it stands, Time Stop freezes everyone else and allows you to do whatever you want for that 1d4 + 1 rounds. In high level PvM, this means you can drop Evard's at feet of every Demonologist and watch them die before the Time Stop even ends. In high level PvP, this basically means, that battles are ended with who can first cast Time Stop, adding remarkable power to those with UMD and time to loot enough scrolls, or those who are high level wizards/sorcerers.. As it stands, Time Stop is pretty much,
the universal automatic "I win" -spell, with no saves or limitations whatsoever.
However, granted it seems like a logical change considering AI, since often with 9 seconds duration, the AI manages to mostly stand still and idle until it's Time Stop ends.
Anyhow, here's how Time Stop is laid out in PnP:
Duration: 1d4+1 rounds (apparent time); see text
This spell seems to make time cease to flow for everyone but you. In fact, you speed up so greatly that all other creatures seem frozen, though they are actually still moving at their normal speeds. You are free to act for 1d4+1 rounds of apparent time. Normal and magical fire, cold, gas, and the like can still harm you. While the time stop is in effect, other creatures are invulnerable to your attacks and spells; you cannot target such creatures with any attack or spell. A spell that affects an area and has a duration longer than the remaining duration of the time stop have their normal effects on other creatures once the time stop ends. Most spellcasters use the additional time to improve their defenses, summon allies, or flee from combat.
You cannot move or harm items held, carried, or worn by a creature stuck in normal time, but you can affect any item that is not in another creature’s possession.
You are undetectable while time stop lasts. You cannot enter an area protected by an antimagic field while under the effect of time stop.
Compared to PoTM, during PnP Time Stop, you can not target others, can not use AoE spells that have a duration less than Time Stop, summons do not start to attack others while it lasts, and in no manner can you harm anyone in the area.
The 1d4+1 rounds, on the other hand, on PoTM is well enough to pretty much kill any character.
So my suggestion goes as follows: Either change Time Stop's duration for PCs back to the original 9 seconds, or by spellhooking, disable all spells that target a creature or are instant AoE spells, make summoning spells come only in effect after Time Stop ends, and disable attacking others during the Time Stop.