There were no oak wands or willows in DD. Staves are melee weapons; neither game required or used them for spell casting.
Crossbows can not be sharpened because they are ranged weapons. Realistically, it would have to be the arrows that could be sharpened. Converting normal arrows to power arrows has pretty much the same effect (piercing damage of normal arrows is 5-12, while power arrows do 42-90).
Willows are spiritual based weapons, and the damage is not dependent on how pointy they are.
