I guess i see what you mean about how edna being played as a woman wouldn't affect the show as a whole, but when you pin point it to individual characters, the character of edna would be the worst. It would loose everything that is appealing to it because there is nothing funny about the character. The fact that a man plays the role just makes the individual character funny. But i see what you mean.
"Why do we play with fire?-Why do we run our fingers through the flame?"