The book isn't considered 3rd party.
It is to the game. I mean, if you watch a movie, you don't expect to need to read a book to get (what I would say is) fairly important scene setting info. Why does this apply to a game?
I didn't find the multiple trips through the canyons at all tedious. I mean, the initial trip (Assualt on the Control Room) was all about fighting the Convenant with a big portion in the tank, later it was making your way through the fighting Covenant and Flood on the look out for Banshees.
I quite like it when a game takes you through a familiar area but when in a different situation, such as the Metroid Prime 2 Dark and light worlds, Zelda Light and Dark worlds etc
Albiet Zelda Light and Dark were
different in fairly quantifiable ways... they had twisted landmarks, for one thing. Mirrored darkly, but not repeated. Halo did use it sometimes to good effect - like revisiting the Pillar of Autumn - but when it game to flat corriders and (due to the limitations of the technology) plain canyons and landscapes, retracing your steps was, for me, astonishingly tedious. It's doubly a shame because the game did have it's moments of lovely art design and setpieces, and if they'd carried through that standard with continuous originality, it'd have been ace.
I guess, though, it probably depends how much you like the base gameplay.... I tended to play it to 'see more' rather than finding the shooting particularly inspiring (because I'd played the likes of CoD before) - if you find Halos' weapons, shooty action, etc enthralling it's probably far more fun than I found it.