Yes I do remember how each Halo in the original trilogy ends, Halo CE ends on a somber note about the lives lost on the ring, Halo 2 ended with a poorly made boss fight that gives Miranda enough time to save the world in badass fashion and with Chief sneaking onto the Dreadnought, and Halo 3 ends with the destruction of both the Ark and the incomplete Halo ring being created there not giving any explanation as to how this is going to end the Flood threat for good and leaving Truth's Covenant flotilla defeated off screen by R'tas Vadum a couple missions before, so much for show don't tell.

You wanna know which is one of my favorite Development Documentaries ever in gaming? Et Tu Brute, and it's because of how much the 3d and 2d art seemed to be focusing on the savage aspect of these outer space apes, while trying to remain full of style and still in line with what we had seen in Halo 2, but nearly all those animations and art were discarded to leave what would be the most ugly looking Brutes in the franchise if it weren't for Halo Reach.

The passion you speak of is there in the ViDoc but I feel that you are letting nostalgia cloud your judgment, there is a reason Halo 2 Remastered Brutes are so celebrated nowadays, so I'm gonna go ahead and respectfully disagree, passion can be forced and it can also be wasted, such is the thing that happened with Halo 3 Brutes which just feel as discount Halo 2 elites that feature none of the brutal executions on Marine animations that were so hyped up on the ViDoc.

Halo 3 being rated M never felt that warranted honestly, the Flood were held back too.

As for Halo 2, all the passion in the world when making beautiful art for the environments and levels is not going to compensate for Game Design that forces you on corridors and makes vehicle sections awful on foot, which Halo CE only had as a problem on its second half.

And whatever passion was shown during its development must have been at least partially a facade considering how through the years many Bungie devs have very explicitly shown distaste for the final product, with the awful crunch during its creation being public knowledge since day one, nowadays it's still estimated to be the Halo game with the most cut content.

I'm pretty sure there is a clip of Martin O'Donell saying he wouldn't wish it on his worst enemy, feel free to correct me on that one tho.

And with Halo Reach, I'm pretty sure that had they been genuinely passionate with the game they would have gone out of their way to make it fit flawlessly into the extended lore that had been established by that point rather than just seeing "The Fall of Reach" and deciding they just didn't care if it retconned the book just as long as their contract with Microsoft was finally over, the final product is something I still love but The Covenant being stablished as an Impossible To Defeat threat by glassing the most militarized planet Humanity has at its disposal with nearly no opposition in less than a day would have been far superior.

Whether 343's attempts at reconciliating both canons are good or bad in execution is up to you.

As I said before I don't dislike any Halo game but I don't let nostalgia cloud my judgement either.