I think they, Blizzard, said somewhere that it wouldn't make sense to go by that fact for very long. Plus-skill weapons would yield better results on higher levels. It's just that we haven't seen those items yet.
True.
In other news, poison dart does not seem to be affected by elemental damage. So there's that.
Looks like the beta has been pumped up a notch. Skeleton King hits like a truck.