Well, TNG's main characters weren't allowed to have flaws like the TOS characters had, with perhaps the exception of the short-lived Dr. Polawski's racism against Data. That must have been difficult on the writers in and of itself. (Picard, of course, had that whole Borg-hate thing going on in First Contact, but it was also resolved in that same movie.)

I think they should do a series/episode/movie or something that reveals that the veniere of utopia in the Federation isn't as legitimate as they'd have you believe, sparking some kind of civil war that ultimately makes the Federation stronger in the long run.