Kind of suprised there is even a Wakizashi in this game, given it's relative pointlessness, unless you want to be a shileld wielding Samurai.
Maybe if there was Niten ichi-ryu with a Katana it would work, but it doesn't seem to me that dual wield has a place in M&B. You can't be disarmed in game and your blade won't break during the fighting, so it's a moot. I guess you can wear it for RP, too bad you can't stab yourself with it.