I don’t think dual wielding as it is traditionally portrayed in gaming has much of a place in BB, since, as others have noted, dual wielding was actually incredibly rare historically, and despite the fantasy elements of BB, the mercenary company itself tends toward a very realistic tone.
However, I do think it would be interesting if daggers had the option to be off hand wielded, giving a very minor defense buff and a bonus to riposte (or granting riposte if the primary normally would not allow it). It could add some interesting defensive dynamics to otherwise very lightly armed characters (and NPCs). Still, if push comes to shove, I’d rather not have dual wielding that force it unnaturally into the game.