Katana is one of the world's foremost martial artists. She's not to be underestimated. Wonder Woman can overpower her yes, but Katana would give her a vicious fight before that happened.
That one never really makes much sense to me, does it matter how good your martial arts are if you are still only human? Unless you do a lot of jobbing (or have a magic sword as mentioned above), really someone who moves much faster than a human and can survive bullets (which will impact with much force that the human hand) will still make mincemeat out of you.
That is one of the things I liked about "for the man who has everything", when mongul turns up, Batman didn't even attempt to fight him because "that's out of our league". If that story was written today, he'd push wonder woman out of the way and wrestle him to the ground.
JMS does something similar when he has Spider-man beat the shit out of the kingpin because he is only human and Peter isn't.