I don't understand why WW has to be tall. If you say it's to project power, well that's just applying a traditionally male trait. It's a meaningless social convention that height = good = power. The idea that Wonder Woman has to be as tall as a man is too literal for my taste. It's like wearing shoulder pads.
If Wonder Woman wants to be physically imposing, she can hover about someone's height and flex her guns. Personally I care more that she doesn't look weak than her being tall. Gina Carano is 5' 8" and that's around the average for most actresses. She certainly looks tough on film and it doesn't have to do with height.
On the other hand, you could say the Amazons are genetically taller, but I imagine they come in all sizes.