I've only watched The Arsenal of Freedom so far, and the new extras. I wished they'd gotten more into why people like D.C. Fontana left half-way through the first season. Was it all because of Gene and his rewrites?
Also, did anyone see the "Next time on Starrrrr Trek: The Next Generation" promo at the end of the third Stardate Revisited? Looks like we'll get a good insight in the Season 2 set into exactly what happened with Gates McFadden.
It's a well known fact that D.C. Fontana and others quit during the first season because Gene was difficult to work with and constantly rewriting the scripts. There's a documentary out entitled Trek Nation where Fontana talks in depth about this and states that she and Gene did not end of good terms.
As for Gates McFadden's absence in Season 2 it does appear they will go into more details. During the theater event this past Monday there was an extended trailer that showed a clip about Dr. Pulaski. Michael Dorn joked "One minute Gates is out and Diana is in and the next Diana is out and Gates is in." I'm hoping Gates goes into more detail about her departure. The basic story for years has been producers weren't happy with the Crusher character