I love Clockwork recovery.
So, any ideas how to remove the lag fix without bricking it?
It's not that complicated, the problem is that it can seem that way if you don't know how it was applied in the first place. This is why I advocate against most one-click solutions.. Many don't come with an "un-click", and you can't see what's going on behind the scenes.
Always try and do it by hand, from the shell. Then you know what exactly was changed, and someone can easily help you reverse it.
That being said, what the lag fix does is create a 'virtual' partition with a more efficient file system. It then copies your /data to the virtual partition. Then it removes that /data, and creates symbolic links pointing to the new virtual partition. That makes it compatible with most every app that gets installed to /data.
If you can't find another thread/post with someone describing how they undid it, I would jump on IRC when you have time and see if someone in #samsung-fascinate or #android-root will help you out.