After reading through a lot of your experiences with the MCC, it seems a majority of the issues stem from the current community playing the game. Face it, the online MM community has almost always been cancer.
Back in the "good old days" of the OG Halo 2, people cheated a lot, terrible host problems, hit reg was frequently questionable, derankers every other game, and trolls/ragers. Online halo back then was more of a spectacle and therefore the BS was more tolerable.
Unrelated, but it reminds me:
did anyone else memorize their OG Xbox hard drive loading sounds so you could gauruntee a particular DLC map was loaded for MM? GOOD TIMES.