At first I thought it was because of the new resolution, but I changed it and the same thing was going on.... but yeah, as of .45 when I turn horizontally the entire landscape "derezzes" and blurs somewhat. It only does this WHILE I'm turning, once I stop it goes to normal. Can't be 100% sure because I can't check the older versions, but this seems to be new with .45.

considering how much time I spend looking around wildly in AoS, trying to spot snipers or snipees...

Pls provide screenshots.

I think it's a new kind of "motion blur" effect.

No one is sure if it's a bug or a feature.

It was always there, it's a feature of Voxlap and it occurs to counteract FPS drops.

You will see it more now because of the hi-res models.

Screencaps: I was playing again just now...

partial screencap of normal view
http://gyazo.com/2f47d12a5aed1eefdc8aa57c39c4291a.png

partial screencap of "derez"
http://gyazo.com/f94687a713226e661efa8f1cedc58256.png

Again, this happens while turning, and when I stop turning it goes back to normal

It's a "motion blur" effect.

Triplefox is correct. While moving the rendering decreases in order to keep a good frame rate. Looking through a C source file (from an example game by Ken Silverman using VOXLAP) there is a routine which has the label:
//Draw less when turning fast to increase the frame rate

Seeing that Ace Of Spades is based on such examples, it's reasonable to assume Ben Askoy has used this.