Fear for anyone who plays Halo for the story
Let me start my response by quoting you CJ: "One more gripe before I go back to playing the game...."
That statement proves the point I'm about to make. With Halo, the story is nice, but its just the whipped cream on a great piece of pie. Anyone (re:EvilLiev) who is obsessed with the story of Halo must be desperate for new SciFi or something. It has potential but as a colleague of mind put it, its a "just add water" story. It is the gameplay that made everyone buy it. But its a lot easier for people to discuss the story than it is to compare how great it felt when the risk/reward choices forced them to flush out an elite. Only game designers see that kind of stuff.
Even though I may be disappointed in Halo or Halo 2's story, I still like their storytelling. It is a great example of how to tell one in a game. It is more than happy to recede while the gameplay is king.
That said, I thought that the game itself was flat compared to Halo 1. In the original, the gameplay really ramped up. With the introduction of each new enemy and each new level, you could really feel how you were having to change your strategy and improve as you played. With Halo2, that happened some but instead of one nice steep ramp, you get two smaller, shallower ones. The Arbiter sections were fun but it felt more like playing two short games instead of one, more satisfying one. And it didn't help that the whole heretic section had nothing to do with the greater storyline, it was an unnecessary aside.
And I agree that the end is not satisfying in any way. And I don't say this because we don't find out what happened, I understand its a cliffhanger. Its about the gameplay. They never really setup that the fight with the Grey Brute is the end level, so I played the whole thing thinking at least one more level was coming. I remember thinking "if this is the Arbiters final battle, I cant wait to see Master Chief's final battle." And when you see the end cutscene, you believe that another one is coming. Then it ends. I also hate that I didn't get to finish the game as Master Chief. Its those two factors combined that makes it a very hollow ending.