Profoundly visceral visual and auditory hallucinations work wonders, and are another instance of the Void's influence working well. The issue is that it has thus far only been used twice to mislead us, and only once in any kind of narratively-relevant capacity when Wrathion and Sabellian were misled in Aberrus. Otherwise, this has hardly been executed to its fullest potential; there have been no efforts to mislead us in the long-term, and this capacity has not been used to wreak uncertainty. If it were employed in the right places, at the right times, at unpredictable intervals, it could certainly be a far more effective representation of what we're told the Void does to you than a few ominous portents in purple text.