Restoring ALL app data is a bad idea. That's true.I could have sworn that I've read on here multiple times that restoring data to apps, even with TIB, results in problematic operations. If I jumped ROMs but had backed up my apps and data with TIB, if I restore the data ONLY in the new ROM, that should be no problem?
Restoring user installed apps and their data usually works well. Restoring system apps and data across different firmwares has a high likelihood for trouble. Titanium backup stores SOME system data in xml format, making it more likely to restore successfully across firmwares.