Actually the demonstration is the same as the E3 build I think, the location and action chosen for E3 are just advantageous for showing off. Land forms and such in the E3 seen are just better and the rocks are kept at a distance. You can see the same rock textures we saw in the new demo on the rock in the field and the rocks to the left. The grass is the exact same from what we can tell. The bushes too, as we see essentially those same bushes in the new demo. The problem with comparing the two is amplified by two things though: the new demo was off screen and the new demo's region has different types of foliage. The new demo had aspen and what seem to be apple or maybe a smaller breed of oak. The E3 footage had pines and larger oaks. The LOD, however, is the exact same as far as we can tell. But again, it's all off screen, which makes everything look worse. The lighting is certainly still very well done, with lots of dynamic shadows and lighting effects on the grass and so on. Oh, and the E3 demo showed off a lot more particle and lighting effects which weren't available for the new one. So comparing the two is a bit difficult.

People just need to relax a bit. This is just the way Nintendo rolls for games like Zelda.

It's not that common to get info on these types of games much in advance. This is just something to tease the interest in the game. As you might notice the video is very much a slice and dice and they are very well aware of what they want to show you and what not.

I believe it's just a video set in a filler section of the game, possibly with assets lacking or even removed. This they they can give you a quick peek into what's coming. Having people go "AAAAAAW" without revealing that much and once they release more info in FEB, MAR or at E3 they'll up the ante a bit and score again. People take it as a "gameplay trailer" of sorts, but it's better marked as quick peek teaser.

We'll see at E3 I guess what the game actually has to show. Also I'd like to remind you that games like this often get cut into pieces and dev sections work on these individual pieces, basic gameplay elements are put into place and the rest is modeled around that. Tuning of these pieces most often takes place quite late in the dev cycle. So let's say they produce 50 tree models or other foliage. Generic development of the piece is done with a placeholder and later on in the cycle the different assets and models get added to that piece of the game. For a Zelda game I can imagine that with 1 year to go they are just entering this stage.

On a last thought have a look at the video a few times. To me it looks like they are running around the same basic map section again and again from different sides. Every time they reach the end and things like foliage and surrounding tend to get more interesting the video is cut and they show up in the same section of the map.

Check the map of the beginning of the video at 54-60 seconds where the map is zoomed in:

You can see where they are starting out, small mountain/rock ridge, some water/small lake, simple forest.

Also on the map is a second arrow close to the green representing Link. I think this is Epona's location. Very close to where they start.

Than look where they are shooting the rest of the video. coincidence? I don't think so. I think they just selected a very small blurp on the map to run around and basically showing you little things without revealing much about the rest of the game. So I have no worries, it's just a very carefully orchestrated video. Pretending to give you lot's of info, but in itself not showing you much.

If stupid embed don't work, which it does while editing the post, please look here: 

https://www.youtube.com/watch?v=HF9xDrQ9gKQ#t=56