I mean I'm going to believe that you do have a friend at Bungie and take this at face value but for some reason this whole post screams "fake". I can't put my finger on it but here's a few reasons why:

"The Dark Below was almost entirely retooled..."

To what? Strip out all of the missions that should have been there? There's about 2-3 hours of real playtime for new missions/strikes and the raid is half the size of VoG. Not to mention the regurgitation of previous locations for at least one of those missions and a strike.

"Story was never seen as very important before the game released."

http://www.gamespot.com/articles/destiny-writer-quits-bungie-to-work-on-game-of-thr/1100-6421791/

Once again, two years of work by a spectacular head writer who has quit for reasons he cannot disclose due to an NDA to work on Game of Thrones. Story was obviously important to a lot of people who worked years on developing something that never saw the light of day. However, I can see the core mechanics have had a lot of work and seem to be great. Smooth combat, good vehicle design. However, most of these mechanics mimic other projects Bungie has worked on (ex. Halo). I highly doubt they started from scratch on an engine which would mean they had time to focus on the story.

"...there have been basically no server issues in comparison to other major AAA always online releases..."

You mean besides the hundreds if not thousands of posts about how people would get some random animal named error with almost no description of what was happening and patches would actually increase connection issues across the board? How about randomly getting booted to space and removed from your fireteam while still being able to talk in party chat? Or more recently, how about the same exact issue that plagued Halo 2 multiplayer where messing with your direct connection provides a benefit to the player?

As for even putting up any of this information, your friend did pretty well considering he's locked into an NDA where he can be sued into oblivion if he releases the wrong information. Personally, I would not be very happy with you if I found out you were doing this no matter how general you were being. I have many friends who work in the video game industry and discussions like this are meant for the people taking part in them and not the community because you want gush over knowing someone in the inner circle.