That's the definition of BAD storytelling, when you cannot explain what the hell is going on, without relying on outside sources. Say what you will about Bungie games, but I didn't need to read comics, books, watch live action series' to have a semblance of what's going on.
CJ, you just stated while you didn't think the storytelling was bad, NONE of your friends knew who the Didact was, or why he was doing this, etc. What does that say?
You need to explain things, use prior games as the ONLY main source, or explain it in game. Instead of that useless halsey in handcuffs, bullshit, why not give that scene more depth?
Say what you will about Reach (2010) retconning a book that was written in 2001 on Microsoft orders, and yes the book was great, but Reach was polished, had a self contained story. The only real questions were what happens next, or why did this happen/could stuff be prevented?