@Alwarren

That's a general problem of the SSAO/HBAO/HDAO.

I experienced these "black auras" in other games too.

This is the whole point of ambient occlusion.
The point is to produce that black halo (shadows) when the occluder is close enough to a surface. That is the actual goal.
The pictures show really good screen space ambient occlusion, it doesn't look bad.

Here is a screenshot of the ages old Crysis 1 that did SSAO instead of HDAO.
http://upload.wikimedia.org/wikipedia/commons/8/8b/Screen_space_ambient_occlusion.jpg

You can clearly see that the tank casts a shadow on the ground. That is made by SSAO/HDAO.

The pictures show really good screen space ambient occlusion,
it doesn't look bad.

Quite obviously, "looking good" and "looking bad" is a matter of taste. I think these halos look horrible. I don't want to disable AO because in most cases it looks fine, but these...

You can clearly see that the tank casts a shadow on the ground.
That is made by SSAO/HDAO.

I know how SSAO/HDAO works. The shadow under the tank is fine. The halo around characters, not so much. The halo follows the camera view, which a shadow would not.