You are right, all of female characters have smaller and slimmer characters, and sometimes it is really hard to hit them.
What is wrong is sometimes people assume that they are faster. In fact, they have the same speed. My clan has tested a few times. It is just the human eyes that make them look faster. Smaller body, looks faster. Just like a truck going at 50 mph (seems really slow) compared with with a bicycle going with the same speed (pretty darn fast).