Now that I've finished Halo Reach I refuse to believe you played and beat Halo Reach. The games ending has been stuck in my head for hours. It had that much of an impact on me. You are seriously one jaded and harsh critic, or you just ran through it without really paying attention. You can have your opinion, but man is it purplexing. That was by far the best story Bungie has ever produced.
Maybe I'm not jaded or harsh, but you are too forgiving, or are one of the people who wear Halo-goggles and it can do no wrong. There's nothing wrong with being a fan, so don't take that the wrong way. But for everything you like about the campaign, I could easily give a reason why I think it's lame to me. Differing opinions, that's all. For instance, this scene was so laughably bad to me, yet you may enjoy it (somehow):
"There's good news a bad news. Looks like gravity is the only way off this mutha".
"What's the good news?"
"That IS the good news. Bad news is the firing mechanism is fried. Looks like I'm gonna have to set this thing off manually".
"That's a one way ticket."
"We all gotta check out sometime."
If that's not a Michael Bay moment, then I'm not sure what else is. I wasn't sure whether to yawn or laugh.
I will say one thing positive about the campaign though (without a spoiler). I like what happens after the credits. That really captures the mood of what the game should have had more of.