OK, I be the devil's advocate. I think the ATP FH is fundamentally better because it is more compact, quicker to the mark and more efficient (less moving parts). I also think the WTA FH evolved as most WTA pros learned to play when they were under 10 and needed a big swing to whack the heck out of the ball as their cute little pig tails flew up into the air. Specifically, I think laying the racket head back beyond the back is bad technique that should be corrected in rec players. Also, keeping 2 hands on the frame n prep position and waiting for the ball to bounce (roughly) allows you to vary the size of the take back - small when hitting on the rise and bigger when you have a sitter to whack.
So, I agree with op that learning a compact swing is beneficial and should be pursued.
To learn it:
1. reference lock and roll tennis site for the fundamentals
2. keep 2 hands on the racket as you turn shoulders into prep - keep 2 hands on the racket until you start the swing
3. work on swinging by taking a small loop back and down where the racket hand and racket head never go back beyone the plane of your shoulders
In practice rallys, try thinking turn to prep with 2 hands on, small take back and let the racket hand lay back as you pull the core and arm forward.
look at this link and the Henin video at the top of the page - small take back, arm and hand lag core when starting forward - good, simple, clean efficient FH.
http://www.40lovetenniscamp.com/justinehenin
