That was just a teaser trailer. We don't even know where that would be in the game. Maybe he's been woken up several times already (would explain armor changes). And plus, on the story of Reach, Bungie made that, not 343.
I think 343 will do great. In my perspective, they know how to maximize graphics and scenery as well as gameplay just by the Defiant Map Pack. And I wouldn't count Halo: CEA as a new game, it's just a remake. So they've been working on Halo 4 awhile now, and they got until November, maybe later in 2012. They have a lot of time to fix what's wrong and listen to what we want. There will more than likely be a Beta, and they will make changes to the feedback we give.
Halo 4 will definately have the best graphics. But i know you're worried about the storyline. There's so much to do with the story, it could venture from the Halo experience, but I doubt it. I think it'll keep that same feel to it.