Timestop for single player, or purely dungeon bashing enviroments is awesome. In a multiplayer enviroment with pvp? Not so awesome. While the spell itself was indeed very useful for making some dungeons more manageable, in pvp it is just purely unfair, as literally, it is already possible with a mage to obliterate other classes with much ease, even without timestop at all, the near assured damage output of some spells, especially if used in the right order or repetition with the right feats can kill nearly any pc already giving them maybe a couple rounds of swinging on you- who is probably at that level buffed with so many spells they certainly won't be able to kill you without some measure of luck before you can annihilate them. Timestop nerf changes very little in the true power of a mage in pvp -really- only giving the enemy a chance, even if somewhat slim to fight back before you cast the right spells and they are dust. Especially considering how powerful some of the new spells are when combined with metamagic, or used in repetition and proper order.
Honestly, I think we could do without the timestop spell -at all-, BUT, seeing it as a defensive spell is fine as well really, only now instead of being able to use it to crush someone without resistance, you use it to assure your escape almost -every- time if escape is even necessary. Someone beats you down? Timestop, heal potion (the amount of hp those babies restore, its as good as the original spell for a mage), cast maybe a haste, maybe put up another buff that went down- Continue devastation. In trouble again? Repeat. Or if you simply don't want to put up with someone who is charging at you, Timestop, expeditious retreat, gone. No one's catching you. Timestop may not be an instant win button anymore, but it is still very close to an assured escape for any smart and prepared mage. My own Necromancer Adrian Von Viklov had a fine collection of timestop scrolls, and I hate to say it, but I did indeed use them to instant win several pvp's.. It was just too OP as it was.
My points are. The spell is definitely not ruined, it's just been downgraded from an instant win button in pvp, to a still extremely useful and viable emergency button to fix whatever needs fixing, or a near guaranteed great head start in escaping something.
I do lament the loss of power for dungeon bashing, buuuuut, then again I'm sure I am not the only person who will be -overjoyed- that certain horrific spawns won't be able to timestop me and nuke the crap out of me (I vaguely recall a timestop-hellball combo, among other spawns that make brilliant FUBAR use of timestop) without me being able to act in defense at all. Our downgrade, is the enemies downgrade ^_^. I don't argue against however, that some dungeons certainly seem like they required the original timestop, even if we know deep down they truly don't- Still seems like they did, and it certainly takes mages down a notch in being able to dish out some much needed pain to a spawn or boss in said dungeons that if you do not take care of effectively, will chew your party up, and spit them into a blender and make an adventurer smoothie. Then again, DM's and Devs know what they are doing, if somethings become -honestly- impossible to do without original timestop, they will adjust to make it possible i'm sure (Unless you really are just not meant to succeed in killing that said thing, and you should reconsider trying to next time)