Dim vision is a very underused curse by pretty much all necros, but in the form of ravens, it is insanely useful. However there is a difference between the two. Necro’s DV is an area curse. Ravens’ DV is only applied to the target itself.
I am hoping that they can make the ravens’ DV similar to attract, which is also a single target curse, and somehow does not overwrite all other curses (it works with confusion IIRC).
The ravens peck out the eyes of the enemies, so even though the effect may be the same as DV, it’s not really a curse. Another curse shouldn’t overwrite that.