I would say it represents the absolute peak of Halo.
An iteration of linear Forerunner arenas of increasing difficulty that end with a triple Warden fight (that the friendly AI have no capability to deal with), and a surprise ring of floating turrets? Where the whole tactical plan was " I don't know, but we have to keep going forward!" and where the drama centered around Cortana's strange spat with whoever the fuck the Warden is supposed to be?
That's the absolute peak of Halo? Oh God no. Please no.
And it was followed up by a level with even more random logic to it, where the drama centers around trying to free Blue team from a Forerunner meditation sphere (the horror). I still can't believe that that was the plan for the game's finale all along. I just can't.
I wish Halo 5 had more missions like Argent Moon. That intro shows Spartans acting like Spartans (daring+smarts+tricksiness rather than Iron Man brrrap-brrrap everything dies easily opener), each area is bleak with Oni mystery, and the space itself makes for some incredible firefights that take full advantage of the new Spartan move-set (the verticality, the clambering, even walls to charge through, and the spacing that allows you to use your thrusters to great effect) and provides dangers and opportunities at all ranges, including a nice Banshee interlude, and ending with a holdout against covenant and hunters before taking off in your new stealth ship.
Too bad its the random mission level, mostly disconnected from the story, save for The Chief's "vision", that ended up having the most punch to it for me. The fact that my favorite level had no Prometheans in it isn't lost on me either.
Edit: To be sure, I enjoyed a lot of the campaign, mostly because of that new moveset and the multi-faceted environments, but seriously think it fell off a cliff in its final act. And that it had some important missions cut or something.