I know it is still quite early to provide feedback, and that's not why Arcen is releasing the pre-alpha footage. Though reading all those extremely negative comments about AVWW graphics on RPS(they are a lot more positive now, since the last video got released) I thought, it could be helpful to provide some feedback already.
I know that many of the ideas are going to be obvious or simply things that you haven't had time to take care of yet, but if we come up with even a few good ideas or ones that you could have overlooked then it's worth it.
I really love how the foliage looks in motion, and I think that this and similar effects could very well draw people's attention away from the, still criticised, character animations which, according to Chris's blog post, won't see much more polish.
I'm trying to think of stuff that could be reused and modified easily, so that a single solution can provide a variety of effects.
Small objects being carried on the breeze, mostly some absolutely miniature stuff, just a pixel or so on the screen, like wind pollination or single leafs. This could produce a subtle effect that you could use in most outdoor areas, modifying the speed and the types of objects.
Moving clouds are a nice idea, but I think they would be more effective if they weren't visible themselves, only casting the shadow on the ground instead. They could be bigger and thus provide more variation in colour to the scenes, without obscuring the view.
Some simple and subtle post processing, for example; increasing the temperature of the colours in the areas that you have already explored and secured. Of course, those wouldn't have to be tied to gameplay in any way, they seem like a simple way to introduce some more variation to the scenes with little effort.
Inside the old abandoned buildings there could be some dust particles flowing slowly in mid air. A lot more visible if there is a sunbeam coming through the roof perhaps. Also, as the character moves, there could be some subtle particle effect, looking like the dust got disturbed slightly. I realize this is quite specific, but I'm afraid that the indoors may look a bit poor without all that lovely foliage to liven it up.
I had thought of more stuff before, that I forgot now, oh well, it's a wall of text anyway.