A while back is when this started to happen on Rubi Ka 1, in quite a few zones, you can only see MOBs when you are practically in their face. They fade in and out of view at a very close range. I have avoided saying anything about this previously since its such an obvious glitch and thought you'd have it fixed by now. It leads to constant adds when you attack non-aggro mobs and a quick death when you run into groups of aggro mobs, from not being able to see them.
Also I know its not just me, my friends and other ppl I have teamed with experienced the same thing, plus, the afflicted zones are generally deserted. Furthermore, I logged on one of my old chars on Rubi Ka 2 and did not experience this problem in the same zones.
Zones where I constantly experience this problem:
Wailing wastes
Clon****
Longest road
Andromeda
There are others but can't remember them offhand.
You hardly ever see anyone in these zones either, is this what you want? half the gameworld deserted?