Yeah, you're all right but we can already start building the first components that are clearly visible in the trailer. And to do this, we need to analyse the frames of the trailer, but this is not a problem. I already did this for my newest project (described in the conversation "New rc Star Wars Episode VII droid"), so I can also do it again for this.
I've a really good program and the frames that come out are very clear. If you need them, you can just contact me with a message here on RPF and, within 2-3 days, a good .zip file with all the required frames can be in your expert hands.
Hey guys! My name is Juan Fernandez, the artist who did the interpretations of the new trooper helmets. Here is my revised version, based on what I've seen on the trailer. I know its missing a few details here and there ( as it was supposed to be a rough representation) but I think it might help with the overall shape of the helmet and the look they are going for. Hope it helps.