I think from the very first cutscene 343 had trouble with the story. Why was Halsey in chains, and why were they asking that stuff about Chief? Wouldn't that have been the appropriate time to fill in details on the story after Halo 3? The creation of Infinity, the creation of the new Spartan-IV program etc.
I mean the games are the primary medium, wouldn anyone know half the stuff that happened if they never read the new books or watched FUD?
I have friends who have been with me since day 1 of CE, they didn't even know Forerunners were once in war with humans etc. They believed we WERE forerunners. Reading the last bulletin, I can't help but wonder, how many fans of the Halo games, have no clue what the fuck a Bornstellar-Didact or Ur-Didact is.
I get it's a new trilogy, but explain it better in-game, and if you can't fit it in game, don't release.