NDUDE
Smash Ace
Look at her right hip. There's a small, sheathed blade. You can see it more clearly here:
She never had a blade before...
Not in OoT...
...or SSBM!
I think it's just there to look cooler, kinda like Captain Falcon's gun holster (yes, he has a gun holster on his waist) since Sakurai mentioned that he doesn't want to use daggers (see: Snake) since they seem more violent in different parts of the world. Of course, she might use it more as a ninja rather than the way Snake would use it...