I feel like, parts of the story were rushed, and some of the critical story points were lost due to pacing. If campaign was split into a part 1, where you have more of the “hunt” present, and you play as Locke uncovering the mystery of the Chief’s abscence, and his pursuit of 117, then have a finale fight between the two(Locke and chief) where Osiris realizes that Blue Team is just a pawn in Cortana’s plan. And that Cortana is revealed at the end to be the culprit of these disasters.
then part 2 releases a year later with new content, and the finale of Halo 5. Osiris sets out to look for the other half of the Janus Key, in the hopes that it could provide a solution for Cortana’s rampage. Meanwhile, Blue Team investigates another possible location and is joined by the Arbiter who provides tactical information as you play.
on one mission, while playing as Locke, you get hints that Palmer and Locke once had a fling, and there’s some banter between the two. Then in a rare turn of events, Palmer is killed by some Forerunner being, sending Locke down a “by any means nessecary” train of thought in order to stop Cortana. Locke’s mission takes on a “kill Cortana” mantra, where the Chiefs mission is to save her.
but that’s my idea.