Yes, but two people standing still, one has maybe 200 wpf, 6 PS, the other has 100 wpf and 12 PS, the scrawny one seems to do more damage - does the wpf damage increase really have that much of an impact? It seems like there must be more to it than that.
In average gear on my highest PS character, it fairly consistently takes me 3 hits to kill an agi build in gambeson, though the damage calc gives an average value of 61 damage - more than his total hp.
This isn't very scientific, but I'll do some better tests if nobody knows about a low wpf penalty for melee.