Yeah, that trailer is really damn cool, but you know that you don't PLAY any of those things that you just described as awesome, right? I'll just wait for the HBO Cutscene Library to throw those suckers up... I must say, though, the lady doctor is quite a babe.
Even though you might not play the cutscenes, you probably will still feel involved enough that the outcome is determined on how well you perform during your military campaigns. I'm a sucker for the Halo story, so I think I would just enjoy seeing the cut scenes and revealing the story, but the fun gameplay, imho, is a huge bonus. I think it will have a lot of replay value as well because of multiplayer and possibly doing the campaign with different strategies.
The trailer is awesome. It's like one of those jackpot moments where you get to go deeper in the canon than you thought you'd ever see.. like the first time you saw Coruscant in the new sw movies.. you knew it was there, but didn't know what it looked like. Hopefully that is where the comparison ends, however.