That would be... super lame tbh. I understand how characters can use multiple weapons but they have a "signature" weapon that's a sword, so of course, Sakurai goes with the sword. But this is basically adding in a character just to add a character since they'll just get some standard sword Smash sword swings
. Seems really low effort for DLC when an example that you give like Impa can be a ninja/use a naginata instead and it'd be more unique and true to the character.
Maybe a better idea is the character using the sword as a sidearm? Someone like Anna, a merchant, being a master-at-arms and using a variety of weapons including a sword that Hitagi saw.