I'm thinking that the armor in the trailer will not be the same in the game. If you look at this shot from the vid (and I apologize for the low quality)...
...there is no cod piece, the detail in the gauntlet and handplate are severely lacking. And what's up with his left foot? It looks like it's pinched in at the front.
Personally, I think this is just something they whipped together for E3. I'm not a fan of it either. Although, to be honest, I wasn't much of a fan of the Reach armor at first, but now I love it! So, we'll see, I guess.