I know coding is an issue and the cleanest conversion from wand to sword is to change the graphic and the animation. But I think it would be appropriate (if not too difficult to add to to the game) that a Wizard wielding a sword would have the opportunity to swing it any round they chose.
This would involve swords not giving any cards like wands do (and swords currently do), but instead, on the battle screen a melee card that only shows up if the wizard is holding a melee weapon (not part of the players hand) and it would be an option every turn that would allow the wizard to attack.