I like the idea of it working more like the pnp version, but if it did would people still use it? Level 9 slots are valuable.
My thoughts summed up, pretty much. Consider part of the SRD quote from the OP:
Most spellcasters use the additional time to improve their defenses, summon allies, or flee from combat.
Wouldn't Greater Sanctuary serve these ends better, being an 8th level spell with the duration of 1 turn / level? I know GS has been changed on this server, but I don't see any specifications in the 'Spell Changes' info thread. Yet, even if casting defensive or summon spells breaks GS, personally I wouldn't bother selecting Time Stop as a 9th level Sorcerer spell, or give much thought as to devoting a slot for Time Stop as a Wizard if I had GS instead. There would certainly still be advantages to Time Stop, but IMO, not enough to justify it as still being a viable and useful spell (relative to other spells of the same level or of similar function).
Having said that, I also see this as a spell that, as it currently stands, is a tad overpowered. 1d4 + 1 rounds of free action while everything else around you is frozen not only has great potential to turn the tide of a battle, but very well end it before the duration expires. Given it can be cast multiple times and all over again once a mage rests, I see Time Stop as a spell that can drastically reduce the difficulty of a great many PvM encounters, if not all of them. A good many PvM encounters have a certain spell or certain set of tactics that can greatly reduce the difficulty, but it is the sheer versatility of Time Stop that elevates it past a circumstantial tactic and more into the realm of a universal Doomsday spell.
That was simply in terms of PvM. I've noticed a lot of focus on the PvP aspects and implications of this spell, and personally, I wouldn't wish this spell changed on the basis of PvP use. Mind you, I haven't had the distinct pleasure of
wtfpwned by a mage who cast Time Stop, so I can't speak as to whether or not this is an issue that should be addressed. Rather on personal preference, I don't like mechanical changes being made on the basis of PvP that will affect other aspects of the game besides PvP. I tend to avoid flat-out PvP because I want to avoid a situation, at all costs, where I'm left feeling the story and future RP of my character rests solely on mechanical choices I made with that character's build to make them more 'effective'. To keep from drifting off-topic too much, regardless of what other attitudes and approaches toward PvP are, this is a RP server and PvP should only be an instrument to enhance RP. It's an endless battle perfectly balancing mechanics for PvP, and IMO balanced PvP shouldn't be an important focus of a RP server. As I said before, I haven't been in PvP here with a mage who used Time Stop against me before, so if this is more a matter of abuse than balance, I certainly understand the desire to see a change in the spell.
So, given I seem to have address how Time Stop can be underpowered as its PnP equivalent here and how it can be overpowered as it is now, I'll go ahead and make a suggestion.
Time Stop is limited to X number of casts / Y amount of time. I would suggest Time Stop only be allowed cast once every 12 IG hours. I don't see anything inherently wrong with a level 9 spell being able to completely turn the tide of a battle, but I do think being able to cast such a spell multiple times per rest makes it too powerful. With such a limit, IMO, Time Stop retains its usefulness as a level 9 spell, but its use would become more strategic and careful.