I have scanned probably 100 WH's in Low-Sec and close to 80 in HighSec. In that time, it has held true thus far that most WH's I have seen that link to Low-Sec continue to link to Low-Sec as their exits/entrances respawn, resulting in dramatically lower "visitor" traffic within the WH as compared to High-Sec entrance/exits.
The point here is not the obvious one of "High-Sec WH's get more traffic", but rather that it seems like WH's tend to respawn their exits to their own class of Known Space, rather than recycling those exits/entrances equally between Low/High-Sec. Sort of like a "Class 2-Low" and "Class 2-High" sub-classing. So IMHO, a Class 2 found from Low-Sec will likely continue to mostly respawn exits to Low-Sec rather than High-Sec, and vice-versa, even though Class 2's entrances can occur in High and/or Low-Sec equally.
In Low-Sec, nearly every Class 2 WH I found was empty - literally had my pick of the proverbial litter. But in HighSec (0.5-0.8 systems), nearly EVERY WH I have found is populated...
Maybe "Low-Sec" Class 2 systems don't like to hang with their High-Sec cousins, except on special holidays... Snobs.