No, OP, I disagree with you, there are two things that really need to change. first and foremost, the community needs to get over themselves, stop acting like spoiled little kids, stop getting butt hurt over MLG not being a part of Halo.
Second, MP, it's not as easy as you think. Was Halo 3's MP fun? Yes, to some people, and no to others. It's not the weapons, AAs, vehicles, or equipment that's to blame in Halo 4, it's the lack of custom game settings. Things these days are getting to god damn -Yoinking!- simple. And I'm not limiting that to just Halo, I'm also commenting on everything these days.
I much rather have to spend 5 to 10 minutes figuring out how to create a gametype I'll enjoy, vs spending those 5 minutes searching through the simplified settings trying to figure out who get do more advance settings.
OP, and others, there are a large number of people who enjoy each and everyone of the different Halo MP gameplay. Not just Halo 2, not just Halo 3, and not just Halo 4 or Reach. Some of us enjoyed Halo CE's MP* more than Halo 3's.
*before you guys start replying with "Halo CE was never an online MP!", go google Halo Combat Evolved PC, and Halo Custom Edition, and then sit down, shut up, and listen.
Every single new feature added to the game since Halo CE has been hated, and sometimes liked later on. It's a fact of Halo's life, and he's the thing, every single feature in Halo has a place in Halo. Now, with that said, should Halo take a giant step backward and go back to Halo 3's style of MP, NO, it should keep moving forward. But in no way, shape, or form does that mean Halo should look to the past for things it did best. But there are things that Halo did best in the past, that these days people don't value, and sometimes.
People jump on these forums, demand 343i fix Halo, they demand they change Halo back to what it was, they complain Halo is becoming more like COD in line of features, but turn around and suggest that Halo be like COD in the idea of not changing at all each title. And most if not all people who jump on these forums all have the "IT'S MY WAY OR THE -Yoinking!- HIGH WAY!" tude, and it's causing two problems. #1 The community is split, and the divide between each group is so large, you park the moon between them.
#2 the Developers are less willing to listen to the community for ideas, suggestions, and overall feedback because most the threads aren't feedback, but just flat out flaming threads full of hate, and they don't know who to listen too, and who not.
Halo isn't dying, it's the community in general that's dying, and it's taking Halo with it.