You have good points throughout. You would be correct in a lot of these terms if we lived in a perfect world where everyone just went with the flow that the producers have laid out for us. Unfortunately that isn't the case. People like what people like. Whether that's the old way of playing the game or a potentially new style. Evidently the new style that was brought about by 343 isn't as adaptable as we'd like it to be. Evidence being that the game is near death. I understand the COD standpoint, but as much as i hate to say it, they're successful.
Why? Well they've held onto the aspects of the game that people have come to love. I applaud halo for attempting to push forward and branch out, but in many cases they went backwards. Keep what works and add on. That's the best case scenario in my mind. Why get rid of so many maps produced by the creator? Include plenty, then let the community make their own. Don't rely on the players to do it. Why take out ranking? Sure they added CSR, but that came about way to late to really help the game. The visual ranking + social playlists accommodated almost every type of gamer. Now that is cut in half.
As for MLG, it has to be done that way. Just like with any sport in the world, it has set rules and regulations to make the game more skilled based for players. Saying its a bad thing to embrace rules that push for competitive play is like saying "Hey, i hate that i can't travel in basketball. From now on i'm just going to run with the ball instead because i like that better." No. You need to be able to adjust to the situations given and learn how to play with the format that has been set out for us in this particular playlist.
But, lets not forget, when we had visual ranks, it wasn't purely MLG rules you had to play by. There were multiple playlists from slayer, snipers, objectives, FFA and more. Non of these were MLG regulated and still had a ranking system in which you could play against people near your level of skill. If you didn't want to play for a rank, you could play social. A game mode where it's more about playing the game for the fun of it than it is about seeing how well you can do against players with similar skill levels.