OK, pardon the thread revival, but it was a toss-up between this or starting a new thread.
Just watched this episode for the first time in years yesterday. To my knowledge it's a highly regarded episode among fans, but it falls a little short for me. My main issue is that Q practically herds Picard into changing his past, offering him little choice otherwise (You won't just die, you'll have to spend eternity with me!). Thus the motivation for Picard changing his past isn't Picard's own, and it lacks the dramatic oomph of, say, It's a Wonderful Life
, in which the protagonist is ready to kill himself and thinks that everyone would have been better off if he'd never been born.
Of course, if it wasn't really Q, but all in Picard's mind, then that changes everything, and the episode becomes more dramatically satisfying.