I personally think it looks an interesting game, where it tackles the zombie apocalypse in a more "weighty" way, as opposed to L4D and Dead Rising, which tended to be more button mashing crazy (in a good way).
The use of the child I thought was a intriguing move, as it would approach this glaring flaw that most recent zombie media and media in general seems to avoid; kids are human and just a susceptible as adults. Basically it's refreshing to see a franchise invert the Infant Immortality trope. I feel I should point out, whilst I don't have any children of my own, I have a very close relationship with my sister and seven cousins, with all of the latter being under 10. I don't know but I don't connect with the trailer in a "Oh god, what if it was my kids" kind of way. Same with Dead Rising 2 when giving Katy her shots. Obviously I
would react differently if it
was someone I cared about (For this reason I can see, for example, where Geoff and the commenters on
that video are coming from). I guess I just differentiate the characters and my personal emotions more than others (I say that because after friends and family have seen the trailer, the "What if it was my kid" is the archetypal response I've been given).
That said it's not that I don't feel emotions. I think it's incredibly powerful emotionally, and seems to take a more mature view of the whole zombie apocalypse genre.
As for the actual trailer, the use of the kid is most likely headline grabbing to stir up some controversy. I can't see the game getting released allowing the murder of little zombie children. From wikipedia, it seems like it's going to be a 4 man band affair,
possibly with the father being a character.
I also read it was inspired by the old Romero films, which I love to no end and will definitely look into picking this up soon after release.