I'm no expert either, but from what I've seen the rules/stats in WC don't really correlate well with AoS stats. At least this can be said of the original WC cultist warbands (ie. Iron Golems, Untamed Beasts, etc) which all have varying stats in WC as well as each having several niche abilities depending on the cult (avoid veritcal movement for corvus, poison weapons for splintered fangs, etc). In AoS, these units all have the same basic stats (1A/+4/+4/-/1) with a minor unique ability that correlates with their WC ability and minor buffs for the unique looking models within the warband (ogor in iron golems, snakes in splintered fang, etc.) instead of having your regular champion, musician & stnd. bearer.
To be fair tho I haven't really seen too many of the non-cultists cards, but from what I have seen they don't really seem to correlate all that well IMO. For example DoK blood sisters are pretty tanky in WC with 25 or 30 wounds (can't remember exactly) which is similar to the IG Ogor @ 30 wounds. In AoS the sisters only have 2 wnds ea and the ogor 3.
Hm, looking at these two examples, maybe there is a slight, very slight, correlation of approx. 10 WC wnds per 1 in AoS? Doubt it's that straightforward though. I'm sure someone out there on the world-wide webs has tried to correlate the two stats to some extent. You could probably googles it lol