Are the WTA players not strong enough for the WW forehand?
The Advantage of the WW FH is of course that you can swing harder and still Keep it in. however you have to generate that RHS in the first place.
I noticed that a lot of the WTA Players with "ATP FHs" often lack Penetration in their FH (like the italian and spanish Girls who all use the WW finish) and most hard hitting Girls use more of a swing through (against the other shoulder) finish.
the only hard hitting WW women I can remember are henin, kuzneztsova and stosur. are women hitting flatter because they are not strong enough to hit heavy and hard? (obviously stosur and kuznetsova are strong enough but they are probably stronger than the average WTA Player).